CommonListView EntryWidgetClass allows invalid assignment via “Use Selected Asset From Content Browser”

UE - Editor - UI Systems - Jan 6, 2026

CommonListView requires its EntryWidgetClass to implement UserObjectListEntry. This requirement is correctly enforced by the Entry Widget Class dropdown, which filters out widgets that only implemen ...

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 ...

Reflections of Masked Materials incorrect with Lumen HWRT and Max Refraction Bounces > 0

UE - Rendering - Graphics Features - Lumen - Dec 18, 2025

Lumen HWRT Reflections of Masked Materials are incorrect when "r.Lumen.Reflections.HardwareRayTracing.Translucent.MaxRefractionBounces" is greater than 0. The same issue occurs if the Post-Process V ...

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor

UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...

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

UE - Runtime - Anim BP - 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 ...

Cooker is asserting in Class.h on UE 5.7.1

UE - Core - Systems - Dec 18, 2025

From the linked EPS case: ---------------------------- In UE 5.7 there were some changes to how Enum member names are stored. This change introduces an assert when cooking using the Editor Debug e ...

[WorldPartition][CellTransformer] ActorComponents registered with wrong world from UWorldPartition::ApplyRuntimeCellsTransformerStack

UE - World Creation - Worldbuilding Tools - World Partition - Dec 17, 2025

There is a risk of actor components registering with the wrong world when reconstructed from UWorldPartition::ApplyRuntimeCellsTransformerStack. The repro case is arguably a bad usage, but it was th ...

Viewport stuttering during orbit/zoom navigation

UE - Rendering - Graphics Features - Dec 17, 2025

Received a report of persistent stutters in the editor when trying to navigate in the viewport, including asset editor viewports like the Skeletal mesh editor and control rig editor. Hardware used ...

A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction

UE - Runtime - Character - Dec 16, 2025

Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...