FileUploadImproved - allowMultiple - "Invalid output generated for field allowMultiple... Error when processing and converting between data types"

[gbreavin]

Steps to reproduce

1. Create a new Flow
2. Add the FileUploadImproved Component as a screen element - just the Next button is needed
3. Add a checkbox underneath (default value: unchecked), and set the Validate Input that the checkbox must be ticked before proceeding
4. To summarise, the Flow should have the FUI component, a checkbox that is unticked, and validate logic such that the user can't proceed without ticking it
5. Run the Flow - keep hitting the "Finish" button

This behaviour has been confirmed in Chrome.

Expected behaviour

Every click, you should be warned with the error message that was set above

Actual behaviour

Intermittently - about 1 in 6 times - you receive the following error message:

The Lightning Component FileUploadImproved generated invalid output for field allowMultiple. Contact your administrator with these details: Flow encountered an error when processing and converting between data types. Please check the flow and ensure all data types are matched correctly

Clicking again, the problem will likely go away, but keep clicking, and it'll come back at some point.

We have this happening in 5 sandboxes (on preview pods), but not in one of our other sandboxes (on a non-preview pod), and not in Production. All (including Production) are on the same release - Winter '24 Patch 14.8

This was only noticed in our sandboxes this week - the flows were on v57.0, updating to v59.0 does not appear to solve the issue.

There's this known issue, but few other details. Elsewhere there are suggestions that it might be session related i.e. clear browser cache and the problem goes away, but that doesn't seem to be the case.

Screenshots

Debug Logs

See below for some of the details of the network request.

First is the request to the server - this appears to be the same for both failure and success scenarios, so I've only included one. Note that on the way to the server, FileUploadOriginal.allowMultiple is true. This leads me to believe maybe it's something on the server?

Request to server

{
    "actions": [
        {
            "id": "72;a",
            "descriptor": "aura://FlowRuntimeConnectController/ACTION$navigateFlow",
            "callingDescriptor": "UNKNOWN",
            "params": {
                "request": {
                    "action": "FINISH",
                    "serializedState": "AAAA[...]fa8=",
                    "fields": [
                        {
                            "field": "FileUploadOriginal.allowMultiple",
                            "value": true,
                            "isVisible": true
                        },
                        {
                            "field": "FileUploadOriginal.contentDocumentIds",
                            "value": [
                                "06992000002CO6BAAW",
                                "06992000002CRPtAAO"
                            ],
                            "isVisible": true
                        },
                        {
                            "field": "FileUploadOriginal.contentVersionIds",
                            "value": [
                                "068920000031PJXAA2",
                                "068920000031STZAA2"
                            ],
                            "isVisible": true
                        },
                        {
                            "field": "FileUploadOriginal.recordId",
                            "value": "0019200000D4Ng5AAF",
                            "isVisible": true
                        },
                        {
                            "field": "FileUploadOriginal.uploadedFileNames",
                            "value": [
                                "a.csv",
                                "b.csv"
                            ],
                            "isVisible": true
                        },
                        {
                            "field": "Proceed",
                            "value": false,
                            "isVisible": true
                        }
                    ],
                    "uiElementVisited": true,
                    "enableTrace": true,
                    "lcErrors": {}
                }
            }
        }
    ]
}

Now for the responses - one where there is no issue, and the other when an issue occurs. When the issue occurs, it appears the server believes that allowMultiple is null.

Server Response - failure

{
    "actions": [
        {
            "id": "76;a",
            "state": "SUCCESS",
            "returnValue": {
                "error": null,
                "response": {
                    "reactiveFormulas": null,
                    "interviewStatus": "STARTED",
                    "flowLabel": "Debugging Error",
                    "helpText": null,
                    "locationName": "First_screen",
                    "cfvFeatureName": "cfv",
                    "currentFlowVersionId": "3019200000GsdRR",
                    "showHeader": false,
                    "debugTrace": {
                        "entries": [
                            {
                                "html": "<span style=\"font-weight:bold;\">How the Interview Started<\/span><br>\n<span>A User (005Mn000000jMik) started the flow interview.<\/span><br>\n<span>API Version for Running the Flow: 57<\/span><br>\n<\/p>\n"
                            },
                            {
                                "html": "<p>\n<span style=\"font-weight:bold;\">Transaction Committed<\/span><br>\n<span>Any records that the flow was ready to create, update, or delete were committed to the database.<\/span><br>\n<\/p>\n"
                            }
                        ]
                    },
                    "reactivityRules": [],
                    "showFooter": true,
                    "localActionName": null,
                    "localActionOutputs": null,
                    "featureGroupName": "flowclientruntime",
                    "navigationFeatureName": "navigation",
                    "pausedText": null,
                    "serializedEncodedState": "AAAAW3[...]Y4E=",
                    "apiVersionRuntime": 57.0,
                    "localActionInputs": null,
                    "guid": "8001f3a2d0fae0f18970384f5c5118c001f5f1a-75b4",
                    "outputVariables": null,
                    "fields": [
                        {
                            "outputs": [
                                {
                                    "dataType": "STRING",
                                    "name": "acceptedFormats",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "APEX",
                                    "name": "allowMultiple",
                                    "isCollection": false,
                                    "objectType": "Boolean"
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "contentDocumentIds",
                                    "isCollection": true,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "contentVersionIds",
                                    "isCollection": true,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "icon",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "label",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "recordId",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "uploadedFileNames",
                                    "isCollection": true,
                                    "objectType": null
                                }
                            ],
                            "isRequired": false,
                            "regionContainerType": null,
                            "extensionName": "c:fileUploadImproved",
                            "helpText": null,
                            "metadataValues": null,
                            "inputs": [
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "allowMultiple",
                                    "isCollection": false,
                                    "value": null,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_allowMultiple",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "recordId",
                                    "isCollection": false,
                                    "value": "0019200000D4Ng5AAF",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "renderExistingFiles",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_renderExistingFiles",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "renderFilesBelow",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_renderFilesBelow",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "visibleToAllUsers",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_visibleToAllUsers",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                }
                            ],
                            "dataType": "LIGHTNING_COMPONENT_OUTPUT",
                            "errorMessage": "The Lightning Component c:fileUploadImproved generated invalid output for field allowMultiple. Contact your administrator with these details: Flow encountered an error when processing and converting between data types. Please check the flow and ensure all data types are matched correctly.",
                            "isReactiveOnInit": false,
                            "label": null,
                            "extensionType": "lwc",
                            "name": "FileUploadOriginal",
                            "triggersUpdate": false,
                            "choices": null,
                            "contextMap": null,
                            "fields": [],
                            "value": null,
                            "fieldType": "COMPONENT_INSTANCE",
                            "visibilityRule": null,
                            "valueSources": null
                        },
                        {
                            "outputs": null,
                            "isRequired": false,
                            "regionContainerType": null,
                            "helpText": null,
                            "metadataValues": null,
                            "inputs": null,
                            "dataType": "BOOLEAN",
                            "errorMessage": "<p>Can&#39;t proceed!<\/p>",
                            "isReactiveOnInit": false,
                            "label": "Proceed",
                            "name": "Proceed",
                            "triggersUpdate": false,
                            "choices": null,
                            "contextMap": null,
                            "fields": [],
                            "value": false,
                            "fieldType": "INPUT",
                            "visibilityRule": null,
                            "valueSources": null
                        }
                    ],
                    "actions": [
                        {
                            "id": "FINISH",
                            "label": "Finish"
                        }
                    ],
                    "errors": null
                }
            },
            "error": []
        }
    ],
    "context": {
        "mode": "PROD",
        "app": "flowruntime:flowDebugLightningOut",
        "pathPrefix": "",
        "fwuid": "MDM0c01pMVUtd244bVVLc2VRYzQ2UWRkdk8xRWxIam5GeGw0LU1mRHRYQ3cyNDYuMTUuNS0zLjAuNA",
        "mlr": 1,
        "uad": 1,
        "descriptorUids": {
            "markup://c:fileUploadImproved": "gT6QmmZp2WQMBaqjxH8kSw"
        },
        "loaded": {
            "APPLICATION@markup://flowruntime:flowDebugLightningOut": "8x5eTo4iHlkTdJsxvrUC8w"
        },
        "globalValueProviders": [
            {
                "type": "$Global",
                "values": {
                    "eswConfigDeveloperName": {
                        "writable": true,
                        "defaultValue": ""
                    },
                    "isVoiceOver": {
                        "writable": true,
                        "defaultValue": false
                    },
                    "setupAppContextId": {
                        "writable": true,
                        "defaultValue": ""
                    },
                    "density": {
                        "writable": true,
                        "defaultValue": ""
                    },
                    "srcdoc": {
                        "writable": false,
                        "defaultValue": false
                    },
                    "appContextId": {
                        "writable": true,
                        "defaultValue": ""
                    },
                    "dynamicTypeSize": {
                        "writable": true,
                        "defaultValue": ""
                    }
                }
            },
            {
                "type": "$Label",
                "values": {
                    "LightningPrimitiveCellActions": {
                        "showActions": "Show actions"
                    }
                }
            }
        ],
        "enableAccessChecks": true,
        "dns": "c",
        "rns": [
            "omnistudio"
        ],
        "ls": 1,
        "lairn": [],
        "laerc": [],
        "lav": "59",
        "ln": 1,
        "csp": 1,
        "mna": {
            "lightning": "interop"
        },
        "lff": {
            "ENABLE_MIXED_SHADOW_MODE": false,
            "DISABLE_LIGHT_DOM_UNSCOPED_CSS": true,
            "ENABLE_LEGACY_SCOPE_TOKENS": false
        },
        "arse": 1,
        "acaf": 1,
        "services": [
            "markup://lightning:configProvider",
            "markup://force:salesforceScopedModuleResolver",
            "markup://force:ldsEngineCreator",
            "markup://instrumentation:locatorService"
        ]
    },
    "perfSummary": {
        "version": "core",
        "request": 63,
        "actions": {
            "76;a": {
                "total": 43,
                "db": 8
            }
        },
        "actionsTotal": 43,
        "overhead": 0
    }
}

Server Response - success

{
    "actions": [
        {
            "id": "72;a",
            "state": "SUCCESS",
            "returnValue": {
                "error": null,
                "response": {
                    "reactiveFormulas": null,
                    "interviewStatus": "STARTED",
                    "flowLabel": "Debugging Error",
                    "helpText": null,
                    "locationName": "First_screen",
                    "cfvFeatureName": "cfv",
                    "currentFlowVersionId": "3019200000GsdRR",
                    "showHeader": false,
                    "debugTrace": {
                        "entries": [
                            {
                                "html": "<span style=\"font-weight:bold;\">How the Interview Started<\/span><br>\n<span>Implementation User (005Mn000000jMik) started the flow interview.<\/span><br>\n<span>API Version for Running the Flow: 57<\/span><br>\n<\/p>\n"
                            },
                            {
                                "html": "<p>\n<span style=\"font-weight:bold;\">Transaction Committed<\/span><br>\n<span>Any records that the flow was ready to create, update, or delete were committed to the database.<\/span><br>\n<\/p>\n"
                            }
                        ]
                    },
                    "reactivityRules": [],
                    "showFooter": true,
                    "localActionName": null,
                    "localActionOutputs": null,
                    "featureGroupName": "flowclientruntime",
                    "navigationFeatureName": "navigation",
                    "pausedText": null,
                    "serializedEncodedState": "AAA[...]oGwgpM=",
                    "apiVersionRuntime": 57.0,
                    "localActionInputs": null,
                    "guid": "8001f3a2d0fae0f18970384f5c5118c001f5f1a-75b4",
                    "outputVariables": null,
                    "fields": [
                        {
                            "outputs": [
                                {
                                    "dataType": "STRING",
                                    "name": "acceptedFormats",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "allowMultiple",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "contentDocumentIds",
                                    "isCollection": true,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "contentVersionIds",
                                    "isCollection": true,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "icon",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "label",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "recordId",
                                    "isCollection": false,
                                    "objectType": null
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "uploadedFileNames",
                                    "isCollection": true,
                                    "objectType": null
                                }
                            ],
                            "isRequired": false,
                            "regionContainerType": null,
                            "extensionName": "c:fileUploadImproved",
                            "helpText": null,
                            "metadataValues": null,
                            "inputs": [
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "allowMultiple",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_allowMultiple",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "recordId",
                                    "isCollection": false,
                                    "value": "0019200000D4Ng5AAF",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "renderExistingFiles",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_renderExistingFiles",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "renderFilesBelow",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_renderFilesBelow",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "BOOLEAN",
                                    "name": "visibleToAllUsers",
                                    "isCollection": false,
                                    "value": true,
                                    "objectType": null,
                                    "valueSources": []
                                },
                                {
                                    "dataType": "STRING",
                                    "name": "cb_visibleToAllUsers",
                                    "isCollection": false,
                                    "value": "CB_TRUE",
                                    "objectType": null,
                                    "valueSources": []
                                }
                            ],
                            "dataType": "LIGHTNING_COMPONENT_OUTPUT",
                            "errorMessage": null,
                            "isReactiveOnInit": false,
                            "label": null,
                            "extensionType": "lwc",
                            "name": "FileUploadOriginal",
                            "triggersUpdate": false,
                            "choices": null,
                            "contextMap": null,
                            "fields": [],
                            "value": null,
                            "fieldType": "COMPONENT_INSTANCE",
                            "visibilityRule": null,
                            "valueSources": null
                        },
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                            "outputs": null,
                            "isRequired": false,
                            "regionContainerType": null,
                            "helpText": null,
                            "metadataValues": null,
                            "inputs": null,
                            "dataType": "BOOLEAN",
                            "errorMessage": "<p>Can&#39;t proceed!<\/p>",
                            "isReactiveOnInit": false,
                            "label": "Proceed",
                            "name": "Proceed",
                            "triggersUpdate": false,
                            "choices": null,
                            "contextMap": null,
                            "fields": [],
                            "value": false,
                            "fieldType": "INPUT",
                            "visibilityRule": null,
                            "valueSources": null
                        }
                    ],
                    "actions": [
                        {
                            "id": "FINISH",
                            "label": "Finish"
                        }
                    ],
                    "errors": null
                }
            },
            "error": []
        }
    ],
    "context": {
        "mode": "PROD",
        "app": "flowruntime:flowDebugLightningOut",
        "pathPrefix": "",
        "fwuid": "MDM0c01pMVUtd244bVVLc2VRYzQ2UWRkdk8xRWxIam5GeGw0LU1mRHRYQ3cyNDYuMTUuNS0zLjAuNA",
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        "descriptorUids": {
            "markup://c:fileUploadImproved": "gT6QmmZp2WQMBaqjxH8kSw"
        },
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                    },
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                        "defaultValue": ""
                    },
                    "dynamicTypeSize": {
                        "writable": true,
                        "defaultValue": ""
                    }
                }
            },
            {
                "type": "$Label",
                "values": {
                    "LightningPrimitiveCellActions": {
                        "showActions": "Show actions"
                    }
                }
            }
        ],
        "enableAccessChecks": true,
        "dns": "c",
        "rns": [
            "omnistudio"
        ],
        "ls": 1,
        "lairn": [],
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        "mna": {
            "lightning": "interop"
        },
        "lff": {
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            "DISABLE_LIGHT_DOM_UNSCOPED_CSS": true,
            "ENABLE_LEGACY_SCOPE_TOKENS": false
        },
        "arse": 1,
        "acaf": 1,
        "services": [
            "markup://lightning:configProvider",
            "markup://force:salesforceScopedModuleResolver",
            "markup://force:ldsEngineCreator",
            "markup://instrumentation:locatorService"
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    },
    "perfSummary": {
        "version": "core",
        "request": 59,
        "actions": {
            "72;a": {
                "total": 42,
                "db": 6
            }
        },
        "actionsTotal": 42,
        "overhead": 0
    }
}

[gbreavin]

And so, the weekend comes and goes, and with its passing, the issue mysteriously disappears. We've not changed anything, Salesforce doesn't appear to have applied any patches over the weekend (still on Winter '24 Patch 14.8). We're still keeping an eye out it for now.