Ray tracing scene doesn't reflect WPO with instance custom data

UE - Graphics Features - Ray Tracing - Sep 19, 2025

When 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 - Graphics Features - Nanite - Sep 17, 2025

Nanite 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. ...

Local Exposure can cause large variations in PreExposure under certain conditions

UE - Graphics Features - Sep 16, 2025

PreExposure is influenced by LocalExposure in PostProcessEyeAdaptation.cpp:1265. It appears when the scene is particularly dark and using manual exposure, the LastAverageLocalExposure can read a lar ...

Custom fallback mesh LODs for Nanite-enabled meshes not working

UE - Graphics Features - Nanite - Sep 15, 2025

Creating a custom fallback mesh with LOD for Nanite-enabled meshes with multiple materials, results in mesh LODs with errors. As the number of material sections (material slots) decreases with coars ...

LODs with screen size 0 in legacy assets are incorrectly converted to 1 on load

UE - Graphics Features - Sep 11, 2025

When loading a mesh asset (static or skeletal) created in an old version of Unreal (e.g. 4.10), any LOD whose LOD screen size was originally set to 0, is converted to 1. This causes LODs that would ...

Downsampled SceneColour textures are not invalidated after ComposeToNewSceneColor when TSR is enabled leading to AfterMotionBlur materials not rendering bloom

UE - Graphics Features - Sep 11, 2025

When an emissive AfterMotionBlur material is used with TSR, Bloom is not applied to the material. The cause for this appears to be that AfterMotionBlur materials are composed to a separate texture ...

SkyLight Leaking does not affect reflections when the SkyLight is static but static lighting is disallowed

UE - Graphics Features - Sep 10, 2025

Reflections do not receive SkyLight leakage contribution from a static SkyLight when static lighting is disallowed. This is caused by the function UpdateSkyIrradianceGpuBuffer checking if the SkyLig ...

[AI] Failed check in UMassSpawnerSubsystem::DestroyEntities due to EntityManager still procesing

UE - AI - Mass - Sep 7, 2025

It crashed when unspawning an AI which will destroy its entity. Inside DestroyEntities "IsProcessing" is true, but when it breaks into the debugger, "ProcessingScopeCount" is 0 (so IsProcessing shou ...

Crash when changing r.MaterialQualityLevel when FastGeo plugin enabled in cooked build

UE - World Creation - Worldbuilding Tools - Sep 5, 2025

The engine crashes when the r.MaterialQualityLevel is changed in a cooked game that uses the FastGeo Streaming Plugin. The crash doesn't repro with the same steps in Editor, just in a cooked build. ...