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 ...

Cooker is asserting in Class.h on UE 5.7.1

UE - CoreTech - 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 ...

Unable to interact or collide with geometry collection after Removal on Sleep or Break timer finishes, yet unbroken piece continue to render

UE - Simulation - Core - Dec 18, 2025

Context: A static mesh is able to have a geometry collection generated from it using the Fracture editing mode. It can be fractured in many different ways, and when acted upon by a chaos field agent ...

If a child blueprint class has an Instanced/EditInlineNew object property, that property will always be detected as changed by the property editor (i.e. it will show a "Revert" arrow on that property), even if its properties are identical to the parent.

UE - Framework - Blueprint Editor - Dec 17, 2025

Context: Blueprint classes can use Instanced/EditInlineNew object property specifiers to create and edit subobjects directly in the editor. Problem: If a child blueprint class has an Instanced/Edit ...

Section::TrimSection resulting in bad key values at start and end of trim range

UE - Anim - Sequencer - Dec 17, 2025

The trim process inserts keys at the start or end of the range depending if you specify Trim Left or Right, I'm finding that Trim right is inserting a key at the end of the section that is incorrect ...

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 - 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 - Simulation - Gameplay - 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 ...

ISM Cell Transformer breaks component hierarchy when child component are transformed

UE - World Creation - Worldbuilding Tools - World Partition - Dec 15, 2025

This case is related to [Link Removed] but is not a duplicate.  Please make sure to download the attached project as it's different than the one in the other case.  The problem here is that the ...

Automated tests DynamicSubobjectInstancing and NonNativeInstancedSubobjects (CoreUObject group) fail

UE - Framework - Dec 15, 2025

The DynamicSubobjectInstancing and NonNativeInstancedSubobjects automation tests fail. ...