Changing per layer parameters in a layered material that writes to RVT can cause temporary visual corruption

UE - Rendering Architecture - Sep 12, 2025

When using a layered material that writes to a runtime virtual texture. Sometimes when modifying a layer parameter in the material instance editor. The cached material data in the runtime virtual ...

Enabling STATS causes RenderThread to wait for GPU

UE - Rendering Architecture - RHI - Sep 10, 2025

The licensee noticed that in Development builds, the Render thread times are suspiciously similar to GPU times, and the same thing happens when enabling FORCE_USE_STATS in Test configuration. The is ...

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 ...

Importing FBX that contains a socket from Blender to Unreal, the socket gets rotated by 90° and is scaled by 100

UE - Editor - Content Pipeline - Import and Export - Sep 9, 2025

Context: Sockets are attach points that can be placed on a Static Mesh to attach an object to the static mesh. Problem: Importing an FBX that contains a socket from Blender to Unreal, the socket ge ...

Mover character stuck continuously correcting movement after having a skeletal mesh as movement base

UE - Gameplay - Player Movement - Mover - Sep 8, 2025

Once a mover character has had a skeletal mesh set as its movement base, it appears to get stuck in a desynced state after moving to a static movement base. It is only when the character's movement ...

[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 ...

ensure(PinHelpers::UnresolvedPins.Num() == 0); fails after undoing in the editor

UE - Framework - Blueprint Editor - Sep 6, 2025

The underlying cause is some edge case involving a math expression node, which does some perhaps naive things with a contained graph. ...

Some operations on material instances do not transmit over transactions.

UE - Virtual Production - Tools - Multi-user - Sep 5, 2025

DirectoriesToAlwaysCook in platform specific configuration files are ignored by the cook process

UE - Platform - Console - Sep 5, 2025

When DirectoriesToAlwaysCook is placed in a platform-specific configuration file, the cook process does not read that entry when cooking content for that platform. The editor is aware of the platfo ...