Unreal Engine Issues
Unreal Engine Issues
Path Tracer Normals Issue
UE - Rendering - Graphics Features - Path Tracer - Oct 29, 2025Path Tracing normal maps reflect light differently than Lit, and do not look accurate. Also observed in //UE/Release-5.6, CL: 45232827 ...
PCG - BiomeSample level crashes when opened with Instanced Stereo enabled
UE - World Creation - Procedural Tools - PCG Component - Oct 29, 2025When the user attempts to open the Biome Sample Level with Instanced Stereo enabled, the editor crashes with a fatal error: Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\RHI\Private\P ...
[AI] Bad entries in NavigationRepository for Box collision with bCanEverAffectNavigation set to false
UE - AI - Navigation - Oct 26, 2025Some components continue to dirty the navigation state even if bCanEverAffectNavigation is unchecked. Behavior appears very similar to an existing bug, [Link Removed] ([Link Removed]), which invol ...
Mutable compile hangs indefinitely when using Customizable Object Extension Data Constants
UE - Anim - Mutable - Oct 25, 2025I am getting a CO compile to hang indefinitely while compiling. It seems to be caused by the optimization in LocalLogicOptimiserAST that tries to convert 3+ conditionals into a switch statement. It ...
SetGamePause does not affect Sequencer pause if using audio clock as source
UE - Audio - Sequencer - Oct 24, 2025We’ve run into some unexpected behavior when combining SetGamePause(true) with Level Sequences. When calling SetGamePause(true) while a Level Sequence is playing, the visuals pause correctly, b ...
“None” option removed from “Preview Game Language” in Editor Preferences since UE 5.6
UE - Editor - UI Systems - Oct 24, 2025In Unreal Engine 5.5 and earlier, users could select “None” as the Preview Game Language in the Editor Preferences. Starting from UE 5.6, this “None” option is no longer available. Based on source ...
Lumen reflections break when the normals don't match the pixel depth information.
UE - Rendering - Graphics Features - Lumen - Oct 23, 2025Lumen Reflections can leave black spots in chrome materials with strong normals. Also tested on UE 5.5, CL: 41545209 and UE 5.6, CL: 45232827 ...
RuntimeCellTransformers can result in increasing the instance count when a BP instance is not destroyed.
UE - World Creation - Worldbuilding Tools - Oct 22, 2025The problem is related to the SimpleConstructionScript that executes on the BP instances after the transformer. The problem also happens at cook time as the SCS is executed when the package is sav ...
World Position Offset invalidates Point Lights Entire Virtual Shadow Map Cache when light frustrum is only overlapping a small portion of the mesh
UE - Rendering - Graphics Features - Oct 22, 2025When adding a spotlight to the scene it does not correctly use cached virtual shadow map pages when the spotlight overlaps a mesh using WPO. This can be most easily observed by entering 'Cached Pag ...
Children of editor-only actors do not maintain correct transforms when placed inside level instances for PIE and cooked builds
UE - World Creation - Worldbuilding Tools - Level Instances - Oct 20, 2025We have found an issue where children of editor-only actors get wrong transforms in PIE and cooked builds when placed inside level instances. This affects both engine version 5.5 and 5.6. The issue ...