Common UI - commonUserWidget causes assertion failure.

[OmerK]

I have recently enabled CommonUI.
When I have widgets inherited from CommonUserWidget, I get the following ensure condition failure (which also prevents me from packaging the game). When I change the parent class to CommonActivatableWidget it doesn’t hit that assertion.
Am I using it wrong? Do I have to use the activatable widget for all of my UI?

UObjectGlobals.cpp line 2446

	if (bCreatingCDO)
	{
		check(InClass->GetClass());
		ensure(!GIsDuplicatingClassForReinstancing || InClass->HasAnyClassFlags(CLASS_Native));
		InName = InClass->GetDefaultObjectName();
		// never call PostLoad on class default objects
		InFlags &= ~(RF_NeedPostLoad|RF_NeedPostLoadSubobjects);
	}