Unreal Engine Issues
Unreal Engine Issues
HISM flickering when any character is visible
UE - Graphics Features - Jan 12, 2026On an NVIDIA GPU, Instanced Static Meshes can flicker when a Groom card or mesh LOD is visible. This appears related to an issue rendering the ISM into the Scene Depth. At the end of the Prepass, t ...
Light Function Materials containing a Texture Sample and Rotator nodes will fail RHI Validation
UE - Rendering Architecture - RHI - Jan 12, 2026Using a Light Function Material that contains a Texture Sample and Rotator nodes will cause RHI Validation to fail with the following error: LogOutputDevice: Error: Ensure condition failed: Bindings ...
Lumen Global Distance Field Trace Leaking due to Surface Cache Sampling
UE - Graphics Features - Jan 12, 2026At specific distances from a thin wall, surfaces inside of a sealed chamber can receive indirect lighting from outside, leaking light into the chamber. This appears to be due to how SWRT handles sa ...
Temporal blur artifacts on Geometry Cache Components in Blueprint actor
UE - Graphics Features - Jan 9, 2026When a Geometry Collection is in a Blueprint, attached to other components, it can render incorrect motion vectors at some angles. In the test project, any angle that is not a multiple of 45 will re ...
Velocity Scene Texture Data Integrity Issues
UE - Graphics Features - Jan 8, 2026When a Post-Process Material uses the Scene Texture Material Expression, the following code is generated: ``` MaterialFloat2 Local0 = Parameters.TexCoords[0].xy; MaterialFloat2 Local1 = ClampSceneT ...
Inconsistent Behavior in TextureLODGroups when setting NumStreamedMips=0
UE - Rendering Architecture - Jan 8, 2026A licensee has reported that it is not possible to disable texture streaming of a given TextureLODGroup by setting "NumStreamedMips=0" in their device profiles. Currently, using 0 results in the sam ...
OverrideVertexColor causes a crash on mobile renderer
UE - Platform - Mobile - Jan 8, 2026Setting Allow CPU Access on the mesh, or setting bSupportsManualVertexFetch=1 in Engine.ini, avoids the crash. ...
Global Weight of Slot Node is incorrect when fetched after using a Pose Cache
UE - Anim - Runtime - Anim Blueprints - Jan 7, 2026When a montage slot node output is pushed to a Pose Cache and used in a Two-Way Blend, the value returned by GetSlotNodeGlobalWeight will be the current fractional value rather than the actual globa ...
FViewElementPDI::DrawLine calls for SDPG_World are not rendered in PIE or in Game
UE - Rendering Architecture - RHI - Jan 7, 2026When View.Family->EngineShowFlags.CompositeEditorPrimitives is false in the function RenderEditorPrimitivesForDPG. This code picks which version of the batched lines to renderconst FBatchedElements ...
Morph Targets fail to reset to zero
UE - Rendering Architecture - RHI - Jan 6, 2026"We have encountered a regression in UE 5.7 where Skeletal Mesh Morph Targets do not visually reset when all weights are set to 0.0. The mesh retains the deformation from the previous frame. This i ...