Reparenting a non-widget BP A to UUserWidget then reparenting a widget BP B to A causes an assert when compiled

Fatal error: [File:D:\Build\++UE4+Release-4.19+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\Templates\Casts.cpp] [Line: 10] Cast of BlueprintGeneratedClass /Game/UI/Widget_MenuPrincipal.SKEL_Widget_MenuPrincipal_C to WidgetBlueprintGeneratedClass failed

UE4Editor_CoreUObject!CastLogError() [casts.cpp:11]
UE4Editor_UMGEditor!CastChecked<UWidgetBlueprintGeneratedClass,UBlueprintGeneratedClass>() [casts.h:217]
UE4Editor_UMGEditor!FWidgetBlueprintCompiler::OnNewClassSet() [widgetblueprintcompiler.cpp:594]
UE4Editor_KismetCompiler!FKismetCompilerContext::CleanAndSanitizeClass() [kismetcompiler.cpp:250]
UE4Editor_UMGEditor!FWidgetBlueprintCompiler::CleanAndSanitizeClass() [widgetblueprintcompiler.cpp:186]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::FastGenerateSkeletonClass() [blueprintcompilationmanager.cpp:1542]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::FlushCompilationQueueImpl() [blueprintcompilationmanager.cpp:585]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::CompileSynchronouslyImpl() [blueprintcompilationmanager.cpp:201]
UE4Editor_UnrealEd!FKismetEditorUtilities::CompileBlueprint() [kismet2.cpp:741]
UE4Editor_Kismet!FBlueprintEditor::Compile() [blueprinteditor.cpp:3180]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper<void> __cdecl() [delegateinstancesimpl.h:269]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl() [delegateinstancesimpl.h:345]
UE4Editor_Slate!FUICommandList::ExecuteAction() [uicommandlist.cpp:97]
UE4Editor_Slate!SToolBarButtonBlock::OnClicked() [stoolbarbuttonblock.cpp:300]
UE4Editor_Slate!TMemberFunctionCaller<SToolBarButtonBlock,FReply() [delegateinstanceinterface.h:156]
UE4Editor_Slate!UE4Tuple_Private::TTupleImpl<TIntegerSequence<unsigned int> >::ApplyAfter<TMemberFunctionCaller<SToolBarButtonBlock,FReply() [tuple.h:498]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SToolBarButtonBlock,0,FReply __cdecl() [delegateinstancesimpl.h:269]
UE4Editor_Slate!TBaseDelegate<FReply>::Execute() [delegatesignatureimpl.inl:537]
UE4Editor_Slate!SButton::OnMouseButtonUp() [sbutton.cpp:282]
UE4Editor_Slate!<lambda_1002768c627006711ef2f351a87ec0e7>::operator() [slateapplication.cpp:5440]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_1002768c627006711ef2f351a87ec0e7> >() [slateapplication.cpp:266]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [slateapplication.cpp:5429]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [slateapplication.cpp:5927]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [slateapplication.cpp:5907]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [windowsapplication.cpp:1726]
UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [windowsapplication.cpp:2172]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [windowsapplication.cpp:889]
UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [windowsapplication.cpp:726]
user32!UserCallWinProcCheckWow()
user32!DispatchMessageWorker()
UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [windowsplatformapplicationmisc.cpp:129]
UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:3263]
UE4Editor!GuardedMain() [launch.cpp:166]
UE4Editor!GuardedMainWrapper() [launchwindows.cpp:134]
UE4Editor!WinMain() [launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [exe_common.inl:253]
kernel32!BaseThreadInitThunk()
ntdll!RtlUserThreadStart()