Updating a material layer may not update materials that are using that material layer instance

#if WITH_EDITOR
//workaround begin
void UMaterialFunctionInstance::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	StateId = Parent ? Parent->StateId : FGuid(); 
	Super::PostEditChangeProperty(PropertyChangedEvent);
}
//workaround end

#endif // WITH_EDITOR
void UMaterialFunctionInstance::PostLoad()
{
	Super::PostLoad();

	if (Parent)
	{
		Parent->ConditionalPostLoad();
		StateId = Parent->StateId;		//workaround
	}
}

class UMaterialFunctionInstance : public UMaterialFunctionInterface
{
...
	virtual bool ValidateFunctionUsage(class FMaterialCompiler* Compiler, const FFunctionExpressionOutput& Output) override;

#if WITH_EDITOR	//workaround begin
	virtual void PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent) override;
#endif // WITH_EDITOR //workaround end
	virtual void PostLoad() override;

void UMaterialEditingLibrary::UpdateMaterialFunction(UMaterialFunctionInterface* MaterialFunction, UMaterial* PreviewMaterial)
{
...
			// Go through all function instances in memory and update them if they are children
			for (TObjectIterator<UMaterialFunctionInstance> It; It; ++It)
			{
				UMaterialFunctionInstance* FunctionInstance = *It;

				TArray<UMaterialFunctionInterface*> Functions;
				FunctionInstance->GetDependentFunctions(Functions);
				if (Functions.Contains(MaterialFunction))
				{
					FunctionInstance->UpdateParameterSet();
					FunctionInstance->PostEditChange();	//workaround
					FunctionInstance->MarkPackageDirty();
				}
			}