Crash in the Blueprint Debugger.

After creating a few different Blueprints in the editor and adding a breakpoint to a Function, a crash ensues when using Step In to debug the Blueprint.

User sample project provided in attachments.

1. Create or open a UE4 project
2. Create a Blueprint interface "BI_Test" add "TestFunc" function
3. Create a Blueprint actor object "BP_TestDummy" add the Blueprint interface as the implemented interface
4. Create a 2nd Blueprint actor object "BP_ExecTest" in Event Begin add spawning "BP_TestDummy and invoke "TestFunc" in a spawned object
5. Place "BP_ExecTest" into the scene
6. Place a breakpoint in the "Invoke TestFunc" node
7. Start PIE
8. When the breakpoint is reached, press "Step In" twice

Results: The editor crashes.

LoginId:2425c04a4245ea67c3691fbe9144aff0
EpicAccountId:6b50d04f360f4c7587a1171ba17d6a2a

Assertion failed: ObjectToFocusOn [Link Removed] [Line: 1854]

UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:414]
UE4Editor_UnrealEd!FKismetEditorUtilities::GetIBlueprintEditorForObject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:1857]
UE4Editor_UnrealEd!FKismetEditorUtilities::BringKismetToFocusAttentionOnObject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:1943]
UE4Editor_UnrealEd!FKismetDebugUtilities::AttemptToBreakExecution() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetdebugutilities.cpp:628]
UE4Editor_UnrealEd!FKismetDebugUtilities::OnScriptException() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetdebugutilities.cpp:355]
UE4Editor_UnrealEd!TBaseStaticDelegateInstance<void __cdecl(UObject const * __ptr64,FFrame const & __ptr64,FBlueprintExceptionInfo const & __ptr64)>::ExecuteIfSafe() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:1027]
UE4Editor_CoreUObject!TBaseMulticastDelegate<void,UObject const * __ptr64,FFrame const & __ptr64,FBlueprintExceptionInfo const & __ptr64>::Broadcast() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:937]
UE4Editor_CoreUObject!FBlueprintCoreDelegates::ThrowScriptException() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:163]
UE4Editor_CoreUObject!UObject::execTracepoint() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1580]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor_CoreUObject!UObject::ProcessContextOpcode() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2167]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4515]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1314]
UE4Editor_Engine!AActor::ProcessEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:693]
UE4Editor_Engine!AActor::BeginPlay() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:3192]
UE4Editor_Engine!AActor::DispatchBeginPlay() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:3160]
UE4Editor_Engine!AWorldSettings::NotifyBeginPlay() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\worldsettings.cpp:187]
UE4Editor_Engine!AGameStateBase::HandleBeginPlay() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\gamestatebase.cpp:177]
UE4Editor_Engine!UWorld::BeginPlay() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\world.cpp:3505]
UE4Editor_Engine!UGameInstance::StartPlayInEditorGameInstance() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\gameinstance.cpp:355]
UE4Editor_UnrealEd!UEditorEngine::CreatePIEGameInstance() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:3273]
UE4Editor_UnrealEd!UEditorEngine::PlayInEditor() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:2409]
UE4Editor_UnrealEd!UEditorEngine::StartQueuedPlayMapRequest() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:1270]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1558]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:396]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3296]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
kernel32
ntdll

Crash, in the Blueprint Debugger