Description

When using the Event Track to call an event in the Level Blueprint that stops a LevelSequence and then assigns that LevelSequence from another will result in an Access Violation.

Steps to Reproduce
  1. Create new Third Person C++ project
  2. Run project from Visual Studio as Development Editor
  3. Create two LevelSequences named, "Anim1" and "Anim2"
  4. Open Anim1 and add an Event Track
  5. In middle of Event Track, add Event.
  6. Right click Event and go to Properties, change "Value" to "TestEvent"
  7. Save Anim1 and drag it and Anim2 into the Level.
  8. Set both Anim1 and Anim2 to "Auto Play"
  9. Open Level Blueprint and fill out Blueprint logic from attached screenshot.
  10. Save all files
  11. PIE

RESULT:

Access violation on line 800 of BitArray.h

EXPECTED:

No Access violation

Callstack

Access violation reading location 0xFFFFFFFFFFFFFFFF

>	UE4Editor-MovieScene.dll!TConstSetBitIterator<FDefaultBitArrayAllocator>::FindFirstSetBit() Line 800	C++
 	UE4Editor-MovieScene.dll!FMovieSceneSequenceInstance::UpdatePassSingle(EMovieSceneUpdateData & UpdateData, IMovieScenePlayer & Player) Line 240	C++
 	UE4Editor-MovieScene.dll!FMovieSceneSequenceInstance::Update(EMovieSceneUpdateData & UpdateData, IMovieScenePlayer & Player) Line 184	C++
 	UE4Editor-LevelSequence.dll!ULevelSequencePlayer::UpdateMovieSceneInstance(float CurrentPosition, float PreviousPosition) Line 613	C++
 	UE4Editor-Engine.dll!AActor::TickActor(float DeltaSeconds, ELevelTick TickType, FActorTickFunction & ThisTickFunction) Line 831	C++
 	UE4Editor-Engine.dll!FActorTickFunction::ExecuteTick(float DeltaTime, ELevelTick TickType, ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 112	C++
 	UE4Editor-Engine.dll!FTickFunctionTask::DoTask(ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 251	C++
 	UE4Editor-Engine.dll!TGraphTask<FTickFunctionTask>::ExecuteTask(TArray<FBaseGraphTask *,FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 868	C++
 	UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread(int QueueIndex, bool bAllowStall) Line 932	C++
 	UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit(int QueueIndex) Line 679	C++
 	UE4Editor-Core.dll!FTaskGraphImplementation::WaitUntilTasksComplete(const TArray<TRefCountPtr<FGraphEvent>,TInlineAllocator<4,FDefaultAllocator> > & Tasks, ENamedThreads::Type CurrentThreadIfKnown) Line 1776	C++
 	UE4Editor-Engine.dll!FTickTaskSequencer::ReleaseTickGroup(ETickingGroup WorldTickGroup, bool bBlockTillComplete) Line 520	C++
 	UE4Editor-Engine.dll!FTickTaskManager::RunTickGroup(ETickingGroup Group, bool bBlockTillComplete) Line 1426	C++
 	UE4Editor-Engine.dll!UWorld::RunTickGroup(ETickingGroup Group, bool bBlockTillComplete) Line 706	C++
 	UE4Editor-Engine.dll!UWorld::Tick(ELevelTick TickType, float DeltaSeconds) Line 1275	C++
 	UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1408	C++
 	UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 371	C++
 	UE4Editor.exe!FEngineLoop::Tick() Line 2834	C++
 	UE4Editor.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 156	C++
 	UE4Editor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 191	C++
 	[External Code]	

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Fixed
ComponentAnim - Sequencer
Affects Versions4.13
Target Fix4.15
Fix Commit3163859
Main Commit3178562
CreatedSep 5, 2016
ResolvedOct 21, 2016
UpdatedMay 2, 2018