Unreal Engine Issues
Unreal Engine Issues
Build crash when enabling r.CreateShadersOnLoad=1
UE - Rendering Architecture - Shaders - Nov 10, 2025When "r.CreateShadersOnLoad" is enabled, cooking will crash due to failure to create a shader. This occurs on //UE5/Release-5.5, CL: 41545209 and //UE5/Release-5.6, CL: 45232827 ...
GAS: FActiveGameplayCueContainer::RemoveCue crash while iterating removals when consecutive Cue tags are conditionally added and the conditional effects removed in ascending order
UE - Gameplay - Gameplay Ability System - Nov 4, 2025When removing gameplay effects by tag, if the tag that is being removed has other tags that are dependent on it in a cyclical way an "array out of bounds ' error can be triggered. ...
[AI] Gaps between Nav Mesh tiles in World Partition map causing movement issues
UE - AI - Navigation - Nov 4, 2025Navmesh has seams between some tiles that are actual edges rather than previously found "gaps" where it was a debug rendering issue. Pathfinding does fail between these tiles to go straight across. ...
TOptional value changes in parent BP don't propagate to loaded child BPs
UE - Framework - Blueprint Editor - Oct 27, 2025Context TOptional<T> is a wrapping struct around a type, that lets the property have an set and unset state, in addition to the property's value when set. It is editor exposed: designers can open b ...
Lumen reflections break when the normals don't match the pixel depth information.
UE - 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 ...
World Position Offset invalidates Point Lights Entire Virtual Shadow Map Cache when light frustrum is only overlapping a small portion of the mesh
UE - 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 ...
Body Setup of a Static Mesh with Simple Collision will pass validation, but removing it and using only a Complex collision and setting Collision Complexity "Use Complex as Simple" will fail validation: "Bone None requires at least one collision shape".
UE - Simulation - Gameplay - Oct 20, 2025Context: By default, Unreal Engine creates both simple and complex shapes, then, based on what the user wants (complex query versus simple query), the physics solver will use the corresponding shape ...
HZB Occlusion causes large stalls on the render thread
UE - Rendering Architecture - RHI - Oct 7, 2025HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...
Incorrect Lumen Scene direct lighting when objects behind masked landscape
UE - Graphics Features - Lumen - Oct 5, 2025When objects are placed behind or beneath a masked landscape and r.Lumen.HardwareRayTracing.SurfaceCacheAlphaMasking is enabled, the direct light evaluation is incorrect. There are two workarounds, ...
TMatrix<T>::InverseFast() ensure when running URootMotionModifier_SkewWarp::WarpTranslation().
UE - Anim - Gameplay - Oct 3, 2025URootMotionModifier_SkewWarp::WarpTranslation() uses InverseFast() within a block of code that is only executed if DeltaTranslation is not nearly zero. The ToRootSyncSpace transform the code builds, ...