Unreal Engine Issues
Unreal Engine Issues
Strange intermittent CCD behavior on constrained physics bodies
UE - Simulation - Physics - Oct 23, 2019There is some strange issue with CCD where constrained CCD objects can get velocity nulled when hitting things while constrained, its very hard to reproduce normally in engine but happens often in V ...
Crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() when quickly unloading then loading a sub-world partition
UE - Engine Scaling - Streaming - Data Layers - Mar 6, 2025From licensee: Since we integrated 5.5, we are experiencing a crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() on this line check(ActiveDataLayerNames.IsEmpty() && LoadedDataLayerN ...
check(bRenderStateCreated) fires in SendRenderDynamicData_Concurrent called from FRegisterComponentContext::Process
UE - Rendering - RHI - May 18, 2026FRegisterComponentContext::Process() in ActorComponent.cpp iterates over SendRenderDynamicDataPrimitives and calls SendRenderDynamicData_Concurrent() on each. The existing guard checks ::IsValid(Pri ...
Blueprint CDO contains removed component from parent class
UE - Gameplay - Blueprint - Apr 28, 2015Blueprint CDO contains removed component from parent class. From the AnswerHub post: "It appears that if a component is removed from the C++ class, the CDOs for all of the blueprints remain unchang ...
[CrashReport] UE4Editor_UMG!TBaseDelegate<FMargin>::operator=() [delegatesignatureimpl.inl:381]
UE - Editor - UI Systems - Aug 29, 2017This is a longstanding and common UMG crash that has affected more than 200 users since at least the 4.15 release. User DescriptionsI was working in the UI and undid several last changes in quick s ...
[CrashReport] UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReplaceInstancesOfClass_Inner() [kismetreinstanceutilities.cpp:1880]
UE - Gameplay - Blueprint Compiler - Oct 5, 2017This is a somewhat common crash that has occurred throughout the 4.17 release. Users have not provided any description of their actions when the crash occurred. The callstack is similar to some ol ...
Simulated ability tasks not being cleaned up in UActorChannel::ReplicationMap
UE - Networking - Nov 20, 2018I've noticed the issue occurring in both 4.20.3 (CL 4369336) and 4.21.0 (CL 4541578). The user on AnswerHub has also noticed the issue in 4.20.2 (CL unknown) and claims the issue did not occur in 4. ...
Crash when starting PIE on a World Partition level with a Niagara Component inside nested Child Actor Components
UE - Rendering - Architecture - Niagara - Jun 25, 2024Consider an actor containing a Niagara Particle System Component, which is instantiated from another actor's Child Actor Component. When initializing PIE on a World Partition level containing this s ...
PakFiles: Unmounting PakFile while requests are still in progress causes assertion failure in UnMount
UE - Core - Systems - Mar 31, 2022[Link Removed] Licensee is using the chunk downloader. On Shutdown method of their GameInstance, they call FChunkDownloader->Finalize. When they quit the game (Alt+F4) during a chunck download an a ...
Dragging a BP variable into a category can produce inconsistent results
UE - Gameplay - Blueprint Editor - Jan 18, 2019The drag-onto-category operation is assigning the prettified category name, not the actual category name, resulting in variables that are not actually in the same category, even though they appear t ...