Crash when creating a level sequence player after a level begins its tear-down

It's possible to create a level sequence player in a level that's being torn down. Event end play is one example, but the original report comes from a situations that's harder to avoid. Creating a level sequence player spawns a level sequence actor, which causes the crash if the level is being torn-down.

1. And an Event End Play node to a Level Blueprint
2. From that node call Create Level Sequence Player
3. Set the level sequence to any level sequence asset
4. Compile and save the level
5. PIE
6. Exit PIE (hit ESC)

RESULT

The editor crashes.

> UE4Editor-LevelSequence-Win64-Debug.dll!ULevelSequencePlayer::CreateLevelSequencePlayer(UObject * WorldContextObject, ULevelSequence * InLevelSequence, FMovieSceneSequencePlaybackSettings Settings, ALevelSequenceActor * & OutActor) Line 61 C++
UE4Editor-LevelSequence-Win64-Debug.dll!ULevelSequencePlayer::execCreateLevelSequencePlayer(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 496 C++
UE4Editor-CoreUObject-Win64-Debug.dll!UObject::execCallMathFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 860 C++
UE4Editor-CoreUObject-Win64-Debug.dll!FFrame::Step(UObject * Context, void * const Z_Param__Result) Line 339 C++
UE4Editor-CoreUObject-Win64-Debug.dll!UObject::execLetObj(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 2617 C++
UE4Editor-CoreUObject-Win64-Debug.dll!FFrame::Step(UObject * Context, void * const Z_Param__Result) Line 339 C++
UE4Editor-CoreUObject-Win64-Debug.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 1025 C++
UE4Editor-CoreUObject-Win64-Debug.dll!ProcessScriptFunction<void (_cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param_Result, void[Image Removed](UObject *, FFrame &, void *) ExecFtor) Line 828 C++
UE4Editor-CoreUObject-Win64-Debug.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1058 C++
UE4Editor-CoreUObject-Win64-Debug.dll!UObject::execLocalFinalFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 2923 C++
UE4Editor-CoreUObject-Win64-Debug.dll!FFrame::Step(UObject * Context, void * const Z_Param__Result) Line 339 C++
UE4Editor-CoreUObject-Win64-Debug.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 1025 C++
UE4Editor-CoreUObject-Win64-Debug.dll!UObject::ProcessInternal(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 1086 C++
UE4Editor-CoreUObject-Win64-Debug.dll!UFunction::Invoke(UObject * Obj, FFrame & Stack, void * const Z_Param__Result) Line 5542 C++
UE4Editor-CoreUObject-Win64-Debug.dll!UObject::ProcessEvent(UFunction * Function, void * Parms) Line 1916 C++
UE4Editor-Engine-Win64-Debug.dll!AActor::ProcessEvent(UFunction * Function, void * Parameters) Line 798 C++
UE4Editor-Engine-Win64-Debug.dll!AActor::ReceiveEndPlay(EEndPlayReason::Type EndPlayReason) Line 1884 C++
UE4Editor-Engine-Win64-Debug.dll!AActor::EndPlay(const EEndPlayReason::Type EndPlayReason) Line 2184 C++
UE4Editor-Engine-Win64-Debug.dll!AActor::RouteEndPlay(const EEndPlayReason::Type EndPlayReason) Line 2153 C++
UE4Editor-UnrealEd-Win64-Debug.dll!UEditorEngine::TeardownPlaySession(FWorldContext & PieWorldContext) Line 735 C++
UE4Editor-UnrealEd-Win64-Debug.dll!UEditorEngine::EndPlayMap() Line 295 C++
UE4Editor-UnrealEd-Win64-Debug.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1960 C++
UE4Editor-UnrealEd-Win64-Debug.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 414 C++
UE4Editor-Win64-Debug.exe!FEngineLoop::Tick() Line 4850 C++
UE4Editor-Win64-Debug.exe!EngineTick() Line 63 C++
UE4Editor-Win64-Debug.exe!GuardedMain(const wchar_t * CmdLine) Line 172 C++
UE4Editor-Win64-Debug.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 257 C++