Geometry Collection cluster handles leaking and causing ensures with field systems

UE - Simulation - Physics - Destruction - Aug 26, 2025

Geometry Collection cluster handles leaking and causing ensures with field systems. The licensee has shared their analysis: We have been tracking down an assert that seems to happen occasionally wh ...

LOD glitch when using Control Rig with Import Skeleton node

UE - Anim - Rigging - Control Rig - Aug 26, 2025

In Unreal Engine 5.6 and Main, a glitch occurs when switching between LODs in a character setup that uses a Control Rig to dynamically load the skeleton hierarchy through the Import Skeleton node in ...

Cook non-determinism when serializing UObject pointers pointing to garbage

UE - CoreTech - UObject - Aug 25, 2025

There's a cook determinism issue in the way UObject unversioned serialization handles UObject pointers pointing to garbage. Depending on GC timing, it can either be skipped (as a property matching C ...

"Detaching from existing linker" error messages when running Fixup Redirectors commandlet

UE - World Creation - Worldbuilding Tools - OFPA - Aug 25, 2025

MRQ rendering crashes when there is an empty audio track

UE - Virtual Production - Tools - MRQ - Aug 25, 2025

Heterogeneous Volume Actor causes ensures to trigger in Debug builds

UE - Niagara - Aug 24, 2025

When a heterogeneous volume actor is used with a volume material in a debug build, the following ensures are triggered: Ensure condition failed: UniformBufferValue || EnumHasAnyFlags(AutomaticallyBo ...

UE 5.6 broke the Collaborative Viewer Template pawn's Mouse Look

UE - Gameplay - Aug 24, 2025

UE 5.6 broke the Collaborative Viewer Template pawn's Mouse Look. Creating a 5.6 project based on the Collaborative Viewer Template and Playing-In-Editor, we notice that the Mouse Look functionality ...

Copy-pasting an actor property that is a set of strings adds extra quotes and escapes

UE - Editor - Workflow Systems - Aug 24, 2025

Copy-pasting an actor property that is a set of strings adds extra quotes and escapes. The licensee has reported: The problem doesn't happen for example for properties of types set of integers, nor ...

Copying a grouped MaterialInstanceParameterDetail property that has spaces on it's name does not enclose it in double quotes, and later pasting won't work as expected

UE - Rendering Architecture - Materials - Aug 24, 2025

Copying a grouped MaterialInstanceParameterDetail property that has spaces on it's name does not enclose it in double quotes, and later pasting won't work as expected. The licensee noticed this in a ...

Slow editor/PIE loading of UWorldPartitionHLODSourceActorsFromCell

UE - World Creation - Worldbuilding Tools - World Partition - Aug 22, 2025

Loading UWorldPartitionHLODSourceActorsFromCell takes a lot of time in editor + PIE when it contains a lot of actors per UWorldPartitionHLODSourceActorsFromCell (between 2K and 2K actors). ...