New-IntuneDeviceConfigurationPolicy parameter 'payload' takes System.Byte[] - fails trying conversion to System.Object[]

[fallmake]

I want to create an iosCustomConfiguration in version 6.1902.1.10 by doing the following. The "payload" parameter of New-IntuneDeviceConfigurationPolicy expects System.Byte[], but proceeds to try to convert this into System.Object[] which fails.

Am I doing something wrong?

$encoding = [System.Text.UTF8Encoding]::new()
$configXmlPayload = $encoding.GetBytes($configXml.OuterXml)
$configXmlPayload.GetType()

New-IntuneDeviceConfigurationPolicy `
    -ODataType "#microsoft.graph.iosCustomConfiguration" `
    -displayName "Test" `
    -description "Some text" `
    -payloadName "Test_Payload" `
    -payloadFileName "testpayload.xml" `
    -payload $configXmlPayload

This results in:

IsPublic IsSerial Name                                     BaseType                                                                                                                                     
-------- -------- ----                                     --------                                                                                                                                     
True     True     Byte[]                                   System.Array                                                                                                                                 


Message        : Unable to cast object of type 'System.Byte[]' to type 'System.Object[]'.
Data           : {}
InnerException : 
TargetSite     : System.String ToODataString(System.Object, System.String, Boolean, Boolean)
StackTrace     :    at Microsoft.Intune.PowerShellGraphSDK.ODataTypeUtils.ToODataString(Object value, String oDataTypeFullName, Boolean isArray, Boolean isUrlValue)
                    at Microsoft.Intune.PowerShellGraphSDK.PowerShellCmdlets.ODataCmdletBase.WriteJsonFromProperties(IEnumerable`1 properties, String oDataType)
                    at Microsoft.Intune.PowerShellGraphSDK.PowerShellCmdlets.ODataCmdletBase.Run()
                    at System.Management.Automation.CommandProcessor.ProcessRecord()
HelpLink       : 
Source         : Microsoft.Intune.PowerShellGraphSDK
HResult        : -2147467262