GeneSplicerModule has linking errors in a Development target

MetaHuman - Oct 16, 2025

The FArchiveMemoryStream class is defined in GeneSplicerModule and RigLogicModule. This generate linker error as this doesn't respect the "One Definition Rule"  1>Module.GeneSplicerModule.cpp.ob ...

Mutable - morph does not work for a skinned mesh with more than one uv channel

UE - Anim - Mutable - Oct 16, 2025

The morph functionality fails to change when the skinned mesh contains more than one UV channel in a Customizable Object. ...

Right eye looks worse than left with Deferred

UE - Platform - XR - Oct 16, 2025

[Interchange] FBX - Front Facing X-Axis and Flipped Bone Orientation During Animation

UE - Editor - Content Pipeline - Import and Export - Oct 15, 2025

Actors attached to a skeleton imported through a FBX file with the Front Facing X-Axis option enabled are flipped when the skeleton is animated. ...

Intermittent Content is Missing from Cook errors for objects with Niagara packages

UE - Niagara - Oct 15, 2025

Intermittently when cooking large licensee projects, an error is reported at the end of the cook:LogCook: Error: Content is missing from cook. Source package referenced an object in target package b ...

Light Leak Issue in Modular Buildings (Lumen HZBTraversal)

UE - Graphics Features - Lumen - Oct 14, 2025

Starting in Unreal Engine 5.6, disabling "r.Lumen.ScreenProbeGather.ScreenTraces.HZBTraversal" can lead to light leaking between adjacent or overlapping meshes. Also tested on Release-5.6, CL: 4523 ...

Material Instance Platform Stats don't update when Material Layer parameters are changed

UE - Rendering Architecture - Materials - Oct 14, 2025

The instruction count appears to update properly if the whole asset editor is closed and reopened. ...

Extend Worldpartition Editor Grid Widget

UE - World Creation - Worldbuilding Tools - World Partition - Oct 14, 2025

Licensees are looking into ways of adding visualizations to the editor worldpartition grid widget. In one example case, just adding some lines to show which parts of the wp minimap belong to which s ...

Smart Link inactive by default when NavLink is a ChildActor

UE - AI - Navigation - Oct 14, 2025

When placing a NavLinkProxy in ChildActor, the link is not enabled by default. In this situation, setting SetSmartLinkEnabled to true does not establish the connection. You must first set it to fal ...