Ensure condition failed / Crash on BP Compile after adding variable

Crash when compiling BP (containing user defined struct + object reference) after adding variable.

From UDN:
1. Open project
2. Open MyBP and MyBP_Child in Simplified folder
3. NOTICE: do not close Blueprint editor of MyBP_Child.
4. Go back to MyBP
5. Add any variable to MyBP and try to compile it.

Additional Note from EUS:
After opening the project for the first time, I do not get the crash, but I do see " Ensure condition failed" in output. After re-opening the project (no need to save anything) Trying a second time is when the crash happens

Ensure condition failed: !GIsDuplicatingClassForReinstancing || InClass->HasAnyClassFlags(CLASS_Native) [Link Removed] [Line: 2275]

UE4Editor-Core.dll!FWindowsPlatformStackWalk::StackWalkAndDump() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\windows\windowsplatformstackwalk.cpp:200]
UE4Editor-Core.dll!FDebug::EnsureFailed() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:298]
UE4Editor-Core.dll!FDebug::OptionallyLogFormattedEnsureMessageReturningFalse() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:425]
UE4Editor-CoreUObject.dll!StaticAllocateObject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2275]
UE4Editor-CoreUObject.dll!UClass::CreateDefaultObject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:2724]
UE4Editor-CoreUObject.dll!UClass::GetArchetypeForCDO() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:3765]
UE4Editor-CoreUObject.dll!UObject::GetArchetypeFromRequiredInfo() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectarchetype.cpp:20]
UE4Editor-CoreUObject.dll!UObject::GetArchetype() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\public\uobject\object.h:999]
UE4Editor-CoreUObject.dll!UObject::GetArchetypeFromRequiredInfo() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectarchetype.cpp:31]
UE4Editor-CoreUObject.dll!UObject::GetArchetype() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\public\uobject\object.h:999]
UE4Editor-CoreUObject.dll!UObject::GetArchetypeFromRequiredInfo() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectarchetype.cpp:31]
UE4Editor-CoreUObject.dll!UObjectBaseUtility::IsDefaultSubobject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectbaseutility.cpp:418]
UE4Editor-Engine.dll!<lambda_46d4d9b8f4f5e271d1056e2a7075ff4b>::operator()() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\blueprintgeneratedclass.cpp:80]
UE4Editor-CoreUObject.dll!ForEachObjectWithOuter() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjecthash.cpp:705]
UE4Editor-Engine.dll!UBlueprintGeneratedClass::PostLoad() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\blueprintgeneratedclass.cpp:88]
UE4Editor-CoreUObject.dll!UObject::ConditionalPostLoad() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\obj.cpp:988]
UE4Editor-CoreUObject.dll!StaticDuplicateObjectEx() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2093]
UE4Editor-CoreUObject.dll!StaticDuplicateObject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1946]
UE4Editor-UnrealEd.dll!FBlueprintCompileReinstancer::MoveCDOToNewClass() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetreinstanceutilities.cpp:1483]
UE4Editor-Kismet.dll!MoveSkelCDOAside() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:2096]
UE4Editor-Kismet.dll!FBlueprintCompilationManagerImpl::FlushCompilationQueueImpl() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:556]
UE4Editor-Kismet.dll!FBlueprintCompilationManagerImpl::CompileSynchronouslyImpl() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:199]
UE4Editor-UnrealEd.dll!FKismetEditorUtilities::CompileBlueprint() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:745]
UE4Editor-Kismet.dll!FBlueprintEditor::Compile() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprinteditor.cpp:3181]
UE4Editor-Kismet.dll!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper<void> __cdecl(void)>::Execute() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:327]
UE4Editor-Kismet.dll!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl(void)>::ExecuteIfSafe() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:434]
UE4Editor-Slate.dll!FUICommandList::ExecuteAction() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:97]
UE4Editor-Slate.dll!SToolBarButtonBlock::OnClicked() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\multibox\stoolbarbuttonblock.cpp:300]
UE4Editor-Slate.dll!TMemberFunctionCaller<SToolBarButtonBlock,FReply (__cdecl SToolBarButtonBlock::*)(void) __ptr64>::operator()<>() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstanceinterface.h:165]
UE4Editor-Slate.dll!UE4Tuple_Private::TTupleImpl<TIntegerSequence<unsigned int> >::ApplyAfter<TMemberFunctionCaller<SToolBarButtonBlock,FReply (__cdecl SToolBarButtonBlock::*)(void) __ptr64> >() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\templates\tuple.h:497]
UE4Editor-Slate.dll!TBaseSPMethodDelegateInstance<0,SToolBarButtonBlock,0,FReply __cdecl(void)>::Execute() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:327]
UE4Editor-Slate.dll!TBaseDelegate<FReply>::Execute() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:537]
UE4Editor-Slate.dll!SButton::OnMouseButtonUp() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:282]
UE4Editor-Slate.dll!<lambda_1002768c627006711ef2f351a87ec0e7>::operator()() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5263]
UE4Editor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_1002768c627006711ef2f351a87ec0e7> >() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:234]
UE4Editor-Slate.dll!FSlateApplication::RoutePointerUpEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5252]
UE4Editor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5750]
UE4Editor-Slate.dll!FSlateApplication::OnMouseUp() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5730]
UE4Editor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1725]
UE4Editor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2171]
UE4Editor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:888]
UE4Editor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:725]
USER32.dll!UnknownFunction []
USER32.dll!UnknownFunction []
UE4Editor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:129]
UE4Editor.exe!FEngineLoop::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3220]
UE4Editor.exe!GuardedMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor.exe!GuardedMainWrapper() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor.exe!WinMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor.exe!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
kernel32.dll!UnknownFunction []
ntdll.dll!UnknownFunction []