Unreal Engine Issues
Unreal Engine Issues
Ray tracing scene doesn't reflect WPO with instance custom data
UE - Rendering - Features - Ray Tracing - Sep 19, 2025When custom instance data is used to calculate WPO in a Material and applied to an ISM the WPO value in the Lumen scene (ray tracing scene) is different than the visible scene resulting in incorrect ...
Nanite Skeletal Meshes Invalidate VSM
UE - Rendering - Features - Nanite - Sep 17, 2025Nanite Skeletal Meshes will always invalidate VSMs, even with their Shadow Cache Invalidation Behavior set to Rigid. This does not match the behavior of non-Nanite Skeletal Meshes. ...
Controller::OnPossessedPawnChanged broadcasts (Pawn->null) but not (null->Pawn) during AGameModeBase::RestartPlayer()
UE - Gameplay - Sep 17, 2025Context AController has a blueprint assignable delegate that fires when the possessed pawn changes. This should fire in both singleplayer and networked games. The bug is reproducible in single play ...
Hovering items at bottom right of Content Browser does not display tooltip and causes cursor flicker
UE - Editor - Sep 17, 2025When hovering over items located at the bottom right corner of the Content Browser while the Editor is maximized, the tooltip is not displayed. It seems that the tooltip would extend beyond the edge ...
Cook non-determinism when serializing UObject pointers pointing to garbage
UE - Core - Systems - Aug 25, 2025There's a cook determinism issue in the way UObject unversioned serialization handles UObject pointers pointing to garbage. Depending on GC timing, it can either be skipped (as a property matching C ...
Heterogeneous Volume Actor causes ensures to trigger in Debug builds
UE - Rendering - Architecture - Niagara - Aug 24, 2025When a heterogeneous volume actor is used with a volume material in a debug build, the following ensures are triggered: Ensure condition failed: UniformBufferValue || EnumHasAnyFlags(AutomaticallyBo ...
Missing PSO Precaches in the engine
UE - Rendering - RHI - Aug 20, 2025A licensee wanted to report some missing PSO Precaching they found, which they have fixed locally: 1. UCableComponent doesn't implement CollectPSOPrecacheData or call CheckPSOPrecachingAndBoostPri ...
SSR doesn't reflect Skydome Mesh/Material correctly in Vulkan mobile preview
UE - Platform - Mobile - Systems - Aug 4, 20255.6[Image Removed] 5.5[Image Removed][Link Removed] ...
Hardware Raytracing on Lumen can cause a crash on AMD Radeon GPUs
UE - Rendering - Features - Lumen - Jul 29, 2025Hardware Raytracing support can cause a crash on AMD Radeon GPUs when creating the RT pipeline state. ...
Artifacts appear on translucent particle systems during camera motion blur
UE - Rendering - Architecture - Jul 23, 2025Translucent particle systems exhibit visual artifacts when the camera moves, even though motion vectors are disabled for the particle emitters. While switching the Translucency Pass to "After Motio ...