Unreal Engine Issues
Unreal Engine Issues
UAIPerceptionSystem::Tick() has a chance of not being called after level reloading
UE - AI - Dec 16, 2019UAIPerceptionSystem::Tick() is not called after level reloading. When Debugging, UAIPerceptionSystem::CurrentTime is always 0, and UAIPerceptionSystem::SourcesToRegister always contains sources to ...
Compile on load crashes for classes within an abstract class
UE - Gameplay - Blueprint Compiler - Feb 20, 2021When compiling on load in -game, a blueprint class that inherits from a native class that is marked within and the class that it is within is abstract, a crash will occur when FBlueprintCompilationM ...
[Sound Cue] - Randomizer in Sound Cue always picking first input on level load
UE - Audio - Dec 8, 2022Reproduced 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, 2024When 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 ...
Setting Slate.ShowBatching to 1 makes the entire screen green unexpectedly
UE - Editor - UI Systems - Slate - Jun 19, 2025This issue may have occurred due to a refactoring of the related functionality during the engine update from version 5.4 to 5.5. The main reason is that the randomization of BatchColor doesn't work ...
Niagara - When a Static Switch is used inside a Niagara Function Script with "expose as pin" disabled, its Selector variable is exposed as an input on function call nodes. However, this input incorrectly loses its "static" type.
UE - Niagara - Apr 7, 2025Consider a Niagara Function Script containing a Static Switch node with the "Expose as Pin" option disabled for its selector variable. When the function is called by another Niagara Function or Niag ...
Crash Occurs When Actors are Attached Across Persistent and Sublevels When Levels are Saved
UE - Anim - Sequencer - Dec 12, 2017Can 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 ...
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, 2016Importing 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 ...
Soft References resolved at Runtime result in References to Persistent Assets
UE - Gameplay - Aug 23, 2018It is believed that soft references resolved during runtime, point to the edit time instances of actors instead of the runtime instances. This issue does not reproduce when it is called from an Inp ...
Certain combined Linear/Angular movements cause Client to freeze for several seconds
UE - Simulation - Physics - May 24, 2019When using Replicated Movement, certain combined linear/angular movements cause the client to freeze for several seconds and then catch up to the server. This is a regression from 4.21.2 (CL-4753647 ...