UAIPerceptionSystem::Tick() has a chance of not being called after level reloading

UE - AI - Dec 16, 2019

UAIPerceptionSystem::Tick() is not called after level reloading. When Debugging, UAIPerceptionSystem::CurrentTime is always 0, and UAIPerceptionSystem::SourcesToRegister always contains sources to ...

Pawn's role is incorrect in BeginPlay on client if a multicast RPC is called in BeginPlay on server

UE - Networking - Jun 6, 2022

It seems as though calling a multicast RPC during BeginPlay on the server will cause the new actor to finish spawning on the client before applying any initial replicated data, such as the actor's R ...

[Sound Cue] - Randomizer in Sound Cue always picking first input on level load

UE - Audio - Dec 8, 2022

Reproduced 10/10 times. Issue also occurs in //UE5/Release-5.0 - CL 20979098 Binary. Confirmed NOT a Regression. None of these settings seemed to have any effect:Preselect at Level Load (Random nod ...

LOD dithered fade-out transition does not work since UE5.4

UE - Rendering Architecture - Aug 7, 2024

When DitheredLODTransition is enabled for HierarchicalInstancedStaticMesh, in the previous version (5.1.1), dithering was applied during fade-in/fade-out, but in 5.4.3, dithering is not applied duri ...

SKP Import - Materials for certain groups appear black in Path Tracer when using Keep Hierarchy

TM - Interoperability - Mar 3, 2025

Reported by a client in SF [Link Removed] When importing SKP files using the Keep Hierarchy collapse mode, some imported objects in Groups inside SketchUp will appear black in Path Tracer. Appears ...

Incorrect volume bounds check in FTranslucentLightInjectionCollector::AddLightForInjection

UE - Graphics Features - Apr 8, 2025

The 'VolumeBounds' array in FTranslucentLightInjectionCollector::AddLightForInjection is accessed as a pointer instead of with 'VolumeCascadeIndex' and thus fails bounds checks for the outer volume. ...

BSOD when launching Twinmotion on NVIDIA 50-series GPUs with 576.02 Drivers

TM - Rendering - Apr 22, 2025

Reported from multiple users. NVIDIA RTX 50-series GPU users are reporting BSODs when attempting to launch Twinmotion with the latest drivers installed. The crashes occur on the 576.02 driver versi ...

Crash Occurs When Actors are Attached Across Persistent and Sublevels When Levels are Saved

UE - Anim - Sequencer - Dec 12, 2017

Can attach actors to each other through the use of sequencer even though actors are in different levels which leads to crashing when saving and changing levels F3DAttachTrackEditor::IsActorPickabl ...

Differences in Post Process FX between Minimized and Maximized Viewport

UE - Graphics Features - Apr 19, 2016

When scaling the viewport window using the Maximize/Minimize viewport option, the post processing effects applied to the screen do not scale properly. This issue seemed trivial at first, as the use ...

FBX Transform does not scale skeletal mesh with multiple pieces properly using the Import Uniform Scale option

UE - Editor - Content Pipeline - Import and Export - Aug 15, 2016

Importing a skeletal mesh fbx from blender and setting the Import Uniform Scale option for the mesh to a higher value, like 100, results in only one of the meshes being scaled while the other is lef ...