Constraint Binding ID is broken on attach track when subsequence asset is moved.

UE - Anim - Sequencer - Jan 14, 2026

Moving a level sequence asset that contains actors that are being referenced as a subsequence in an attach track causes the references to drop, even though the subsequence reference is correctly upd ...

Curve Retargeting does not work with SourcePose retarget mode

UE - Anim - Rigging - Retargeting - Jan 14, 2026

Currently we build what source curves we are going to remap is done inside of: FIKRetargetCurveRemapOp::AnimGraphPreUpdateMainThread But in our ikretarget processor code we skip calling that functi ...

HISM flickering when any character is visible

UE - Graphics Features - Jan 12, 2026

On 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 ...

Not possible to force the Skeleton attribute to None on a default asset pipeline preset

UE - Editor - Content Pipeline - Import and Export - Jan 9, 2026

I guess that when the default value of the pipeline is None, the editor will silently pick the skeleton that is in the same folder of where you are importing. If the UI is active you can then force ...

MultiProcessCook Shader Symbols fail to write when two workers race and try to write them at the same time

UE - Foundation - Data Pipeline - Cooker - Jan 4, 2026

When shadersymbols are requested, cooking shaders writes the symbol files into {Project} /Saved/ShaderSymbols/<PlatformName>. These symbols are written by the function FShaderSymbolExport::Write ...

Virtual Memory leak when using specific rendering settings in the template project

UE - Rendering Architecture - RHI - Dec 20, 2025

When a project is run with these settings in a template project, untracked virtual memory increases. Cvars r.GBufferFormat 3 r.Lumen.TraceMeshSDFs 1 r.Lumen.TranslucencyReflections.FrontLayer.Enab ...

Skeletal Mesh BLAS updates when not animating

UE - Rendering Architecture - RHI - Dec 19, 2025

The BLAS for Skeletal Meshes that don't move, or tick get updated every frame even if the animation and skin cache aren't updated. This adds over 1ms to update time. The only exception is if the sk ...

When r.SSR.Stencil is enabled, there is wrong logic observed.

UE - Graphics Features - Dec 19, 2025

When r.SSR.Stencil is enabled, the areas with high roughnesss are not discarded and Unlit materials are incorrectly handled. See the linked EPS case (Additional Info URL) for a full explanation of ...

Call In Editor functions not working in blueprints

UE - Editor - Developer Usability - Dec 19, 2025

Context When selecting a component on an actor, any CallInEditor functions on the component's class appear as buttons in the details panel. Problem The CallInEditor functions don't execute in Blu ...

Editor localization causes the GetLinkedAnimLayerInstanceByGroup function to fail in retrieving the corresponding LinkedAnimLayer within the editor.

UE - Anim - Runtime - Anim Blueprints - Dec 18, 2025

When using other language(such as Chinese) as editor language, the Group Name of the Animation Interface will be localized to Chinese. In editor, the animation blueprint grab the group from metadata ...