Using blueprint debug step into BlueprintInterface function, occur crash.

If StepIn is performed on a module for which the Interface function is not defined, a crash will occur.

1.Open attach project.
2.Open Level Blueprint "NewMap1.umap".
3.Selected BeginPlay Node and input "F9" Key.
4.Exec PIE.
5.Break on BeginPlay and execute StepInto several times to enter InterfaceFunction.
At this time, crash occurred.

Assertion failed: ObjectToFocusOn [Link Removed] [Line: 1866]

KERNELBASE.dll!0x000000002A089E08
UE4Editor-Core.dll!FOutputDeviceWindowsError::Serialize() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:120]
UE4Editor-Core.dll!FOutputDevice::Logf__VA() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:70]
UE4Editor-Core.dll!FDebug::AssertFailed() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:349]
UE4Editor-UnrealEd.dll!FKismetEditorUtilities::GetIBlueprintEditorForObject() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:1869]
UE4Editor-UnrealEd.dll!FKismetEditorUtilities::BringKismetToFocusAttentionOnObject() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:1955]
UE4Editor-UnrealEd.dll!FKismetDebugUtilities::AttemptToBreakExecution() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetdebugutilities.cpp:628]
UE4Editor-UnrealEd.dll!FKismetDebugUtilities::OnScriptException() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\kismet2\kismetdebugutilities.cpp:355]
UE4Editor-UnrealEd.dll!TBaseStaticDelegateInstance<void __cdecl(UObject const * __ptr64,FFrame const & __ptr64,FBlueprintExceptionInfo const & __ptr64)>::ExecuteIfSafe() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:1027]
UE4Editor-CoreUObject.dll!TBaseMulticastDelegate<void,UObject const * __ptr64,FFrame const & __ptr64,FBlueprintExceptionInfo const & __ptr64>::Broadcast() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:937]
UE4Editor-CoreUObject.dll!FBlueprintCoreDelegates::ThrowScriptException() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:163]
UE4Editor-CoreUObject.dll!UObject::execTracepoint() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1605]
UE4Editor-CoreUObject.dll!UObject::ProcessInternal() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor-CoreUObject.dll!UObject::CallFunction() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor-CoreUObject.dll!UObject::ProcessInternal() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor-CoreUObject.dll!UObject::CallFunction() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor-CoreUObject.dll!UObject::ProcessContextOpcode() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2192]
UE4Editor-CoreUObject.dll!UObject::ProcessInternal() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor-CoreUObject.dll!UObject::CallFunction() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor-CoreUObject.dll!UObject::ProcessInternal() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor-CoreUObject.dll!UFunction::Invoke() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4461]
UE4Editor-CoreUObject.dll!UObject::ProcessEvent() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1334]
UE4Editor-Engine.dll!AActor::ProcessEvent() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\actor.cpp:699]
UE4Editor-Engine.dll!AActor::ReceiveBeginPlay()
UE4Editor-Engine.dll!AActor::BeginPlay() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\actor.cpp:3162]
UE4Editor-Engine.dll!AActor::DispatchBeginPlay() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\actor.cpp:3130]
UE4Editor-Engine.dll!AWorldSettings::NotifyBeginPlay() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\worldsettings.cpp:187]
UE4Editor-Engine.dll!AGameStateBase::HandleBeginPlay() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\gamestatebase.cpp:177]
UE4Editor-Engine.dll!UWorld::BeginPlay() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\world.cpp:3436]
UE4Editor-Engine.dll!UGameInstance::StartPlayInEditorGameInstance() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\gameinstance.cpp:340]
UE4Editor-UnrealEd.dll!UEditorEngine::CreatePIEGameInstance() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:3447]
UE4Editor-UnrealEd.dll!UEditorEngine::PlayInEditor() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:2535]
UE4Editor-UnrealEd.dll!UEditorEngine::StartQueuedPlayMapRequest() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:1218]
UE4Editor-UnrealEd.dll!UEditorEngine::Tick() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1549]
UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:402]
UE4Editor.exe!FEngineLoop::Tick() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3215]
UE4Editor.exe!GuardedMain() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor.exe!GuardedMainWrapper() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor.exe!WinMain() [d:\build\++ue4+release-4.17+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!0x000000002B4D2774
ntdll.dll!0x000000002D200D51
ntdll.dll!0x000000002D200D51