diff --git a/src/Bicep.Core.Samples/Files/baselines/TypeDeclarations_LF/main.sourcemap.bicep b/src/Bicep.Core.Samples/Files/baselines/TypeDeclarations_LF/main.sourcemap.bicep
index efc1e67760d..0006414f769 100644
--- a/src/Bicep.Core.Samples/Files/baselines/TypeDeclarations_LF/main.sourcemap.bicep
+++ b/src/Bicep.Core.Samples/Files/baselines/TypeDeclarations_LF/main.sourcemap.bicep
@@ -510,24 +510,6 @@ type discriminatedUnion1 = typeA | typeB
 //@        }
 //@      }
 //@    },
-//@          "a": {
-//@            "$ref": "#/definitions/typeA"
-//@          },
-//@          "b": {
-//@            "$ref": "#/definitions/typeB"
-//@          },
-//@          "a": {
-//@            "$ref": "#/definitions/typeA"
-//@          },
-//@          "b": {
-//@            "$ref": "#/definitions/typeB"
-//@          },
-//@                    "a": {
-//@                      "$ref": "#/definitions/typeA"
-//@                    },
-//@                    "b": {
-//@                      "$ref": "#/definitions/typeB"
-//@                    },
 
 @discriminator('type')
 type discriminatedUnion2 = { type: 'c', value: string } | { type: 'd', value: bool }
@@ -659,6 +641,12 @@ type discriminatedUnion3 = discriminatedUnion1 | discriminatedUnion2 | { type: '
 //@      "discriminator": {
 //@        "propertyName": "type",
 //@        "mapping": {
+//@          "a": {
+//@            "$ref": "#/definitions/typeA"
+//@          },
+//@          "b": {
+//@            "$ref": "#/definitions/typeB"
+//@          },
 //@          "e": {
 //@            "type": "object",
 //@            "properties": {
@@ -684,6 +672,12 @@ type discriminatedUnion4 = discriminatedUnion1 | (discriminatedUnion2 | typeE)
 //@      "discriminator": {
 //@        "propertyName": "type",
 //@        "mapping": {
+//@          "a": {
+//@            "$ref": "#/definitions/typeA"
+//@          },
+//@          "b": {
+//@            "$ref": "#/definitions/typeB"
+//@          },
 //@          "e": {
 //@            "$ref": "#/definitions/typeE"
 //@          }
@@ -855,6 +849,12 @@ type inlineDiscriminatedUnion3 = {
 //@                "discriminator": {
 //@                  "propertyName": "type",
 //@                  "mapping": {
+//@                    "a": {
+//@                      "$ref": "#/definitions/typeA"
+//@                    },
+//@                    "b": {
+//@                      "$ref": "#/definitions/typeB"
+//@                    },
 //@                  }
 //@                }
 //@              }
diff --git a/src/Bicep.Core/Emit/TemplateWriter.cs b/src/Bicep.Core/Emit/TemplateWriter.cs
index 0b70dda0927..e000b6424d7 100644
--- a/src/Bicep.Core/Emit/TemplateWriter.cs
+++ b/src/Bicep.Core/Emit/TemplateWriter.cs
@@ -839,7 +839,7 @@ WildcardImportTypePropertyReferenceExpression or
                     ITypeReferenceAccessExpression => ResolveTypeReferenceExpression(memberExpression) switch
                     {
                         ResolvedInternalReference udtRef => GetDiscriminatedUnionMappingEntries(discriminatorPropertyName, udtRef.Declaration, udtRef),
-                        ResourceDerivedTypeResolution rdtRef => GetDiscriminatedUnionMappingEntries(discriminatorPropertyName, rdtRef, memberExpression.SourceSyntax),
+                        ResourceDerivedTypeResolution rdtRef => GetDiscriminatedUnionMappingEntries(discriminatorPropertyName, rdtRef),
                         _ => throw new UnreachableException(),
                     },
                     _ => GetDiscriminatedUnionMappingEntries(discriminatorPropertyName, memberExpression, null),
@@ -861,9 +861,8 @@ WildcardImportTypePropertyReferenceExpression or
             {
                 yield return ExpressionFactory.CreateObjectProperty(
                     DiscriminatorValue(discriminatorPropertyName, objectUnionMemberExpr.ExpressedObjectType),
-                    memberResolution?.GetTypePropertiesForResolvedReferenceExpression(memberDeclaration.SourceSyntax)
-                        ?? GetTypePropertiesForObjectType(objectUnionMemberExpr),
-                    memberDeclaration.SourceSyntax);
+                    memberResolution?.GetTypePropertiesForResolvedReferenceExpression(sourceSyntax: null)
+                        ?? GetTypePropertiesForObjectType(objectUnionMemberExpr));
             }
             else if (memberDeclaration is DiscriminatedObjectTypeExpression nestedDiscriminatedMemberExpr)
             {
@@ -887,17 +886,15 @@ WildcardImportTypePropertyReferenceExpression or
             }
         }
 
-        private IEnumerable<ObjectPropertyExpression> GetDiscriminatedUnionMappingEntries(
+        private static IEnumerable<ObjectPropertyExpression> GetDiscriminatedUnionMappingEntries(
             string discriminatorPropertyName,
-            ResourceDerivedTypeResolution resolution,
-            SyntaxBase? sourceSyntax)
+            ResourceDerivedTypeResolution resolution)
         {
             if (resolution.DerivedType is ObjectType @object)
             {
                 yield return ExpressionFactory.CreateObjectProperty(
                     DiscriminatorValue(discriminatorPropertyName, @object),
-                    resolution.GetTypePropertiesForResolvedReferenceExpression(sourceSyntax),
-                    sourceSyntax);
+                    resolution.GetTypePropertiesForResolvedReferenceExpression(sourceSyntax: null));
             }
             else if (resolution.DerivedType is DiscriminatedObjectType discriminatedObject)
             {
@@ -911,8 +908,7 @@ WildcardImportTypePropertyReferenceExpression or
 
                     yield return ExpressionFactory.CreateObjectProperty(
                         discriminatorValue,
-                        variantResolution.GetTypePropertiesForResolvedReferenceExpression(sourceSyntax),
-                        sourceSyntax);
+                        variantResolution.GetTypePropertiesForResolvedReferenceExpression(sourceSyntax: null));
                 }
             }
             else