Unreal Engine Issues
Unreal Engine Issues
[Mutable] Morph Targets can be disabled in packaged builds when Mesh Streaming is enabled
UE - Runtime - Mutable - Aug 28, 2026When a Mutable mesh instance is created while the actor spawns at a distance, only the low LODs are generated, and the mesh is created with no Morph Targets registered. Later, when the camera approa ...
FCameraShakePreviewer retains world-outered UCameraShakeBase instances indefinitely, fataling CheckForWorldGCLeaks on editor map change
UE - ACT Character - Sequencer - Aug 21, 2026FCameraShakePreviewer is an FGCObject that strongly references the UCameraShakeBase instances it previews, and creates them outered to the previewed UWorld. Nothing releases them on world teardown, ...
Crash in FMovieSceneNumericVariant::Set when loading a Level Sequence with Custom Time Warp on Android
UE - ACT Character - Sequencer - Aug 14, 2026On Android, loading a Level Sequence fatals in the async loading thread: Assertion failed: (NewValue & ~PAYLOAD_Bits) == 0 MovieSceneNumericVariant.cpp:133 Unable to store a pointer outside of a ...
ImportMeshPaintTextureFromVertexColors only works with "Per Instance Vertex Colors"
UE - Editor - Aug 11, 2026The "Import Vertex Colors" feature in mesh paint mode only works if the instance had vertex color overrides enabled. This is especially problematic for Nanite meshes since usually you can't add act ...
Layered Blend Per Bone nodes evaluate to 0.0 weight with Blend Masks when s.AsyncLoadingThreadEnabled is active in Editor
UE - Runtime - Anim BP - Aug 11, 2026When starting the Editor, Layered Blend Per Bone nodes using Blend Masks inside dynamically linked Anim Layers completely ignore the blend pose (evaluating to 0.0 weight for all bones). Disconnectin ...
Editor crashes when overriding Texture Collection in Material Instance
UE - Rendering - Architecture - Aug 6, 2026When a Material uses the DefaultTextureCollection and a Material Instance overrides it - or vice versa - the Editor will crash. Note: bindlessconfiguration=Minimal or higher must be enabled to use ...
Unreal 5.7 Trace server not working on Rocky 8
UE - Platform - Linux - Aug 6, 2026UnrealTraceServer built on a Rocky 8 machine yields a binary that depends on versions of glibc and glibcxx higher than the 2.28 version provided by Rocky 8.$ ldd UnrealTraceServer./UnrealTraceServer ...
SplineMeshComponent resources leak
UE - Rendering - Features - Aug 3, 2026A race condition occurs in the InitSplineVertexFactory_Internal }}function call, which is distributed across multiple threads. This causes {{FSplineMeshVertexFactory to be instantiated multiple time ...
Color picker widget auto-closes unnecessarily
UE - Editor - Aug 3, 2026A licensee reports that the color picket widget in Unreal Editor closes whenever a blueprint actor (map placed instance of an actor blueprint) receives a property changed event, even if the change e ...
Intermittant motion blur issues in content heavy scenes
UE - Rendering - RHI - Jul 30, 2026When using the following RHI/Render thread/GT sync configuration:r.OneFrameThreadLag 1r.GTSyncType 1 The previous skinning bone data can be corrupted and introduce visual artifacts on everything us ...