Crashes occur when executing MRQ while adding UMG with RetainerBox.

UE - Editor - UI Systems - Slate - Sep 9, 2025

Create an asset containing a RetainerBox in UMG, then add the created UMG to the viewport using AddViewport. Running MRQ after this causes a crash. ...

Iris - removal of fast array item not performed on client when server array contains a non-replicated item

UE - Networking - Iris - Sep 8, 2025

It is possible to add items to a replicated fast array that are not intended to be replicated to the clients. For example, FGameplayAbilitySpecContainer has a custom ShouldWriteFastArrayItem impleme ...

'Malformed sequence hierarchy' ensure hit after modifying sub-sequence tracks

UE - Anim - Sequencer - Sep 5, 2025

It's possible for there to be multiple instances of the same sequence in the evaluation states cache if the same sequence is used in multiple sub-sections. Caches are never removed from the evaluat ...

MRQ - Subgraphs do not evaluate properly in Quick Render

UE - Virtual Production - Tools - MRQ - Sep 4, 2025

Subgraphs do not seem to be evaluating properly with Quick Render. Message from the EPS: "While testing out Quick Render, I've found that subgraph nodes are not being evaluated. Digging into it dee ...

PoseSearch Query is flipped 180 degrees 1 frame after a capsule/actor rotation happens.

UE - Anim - Gameplay - Sep 3, 2025

Using MotionMatching with a PoseSearchSchema with a Trajectory grouping. The query gets rotated to match the capsule/mesh component instead of the offset root/actual location of those bones/trajecto ...

RigVMRegistry : The registry is not locked for writing yet : ensure statement error during cook

UE - Anim - Rigging - Control Rig - Sep 2, 2025

I am seeing an cook failure at the very beginning. It goes away with a retry step via Horde. Please find attached call stack. I am able to consistently reproduce it by wiping all the DDC cache and ...

Material Particle SubUV Sample does not work with Tex Object

UE - Rendering Architecture - Materials - Aug 29, 2025

The Particle SubUV Sample node uses its own texture object reference instead of the one provided by the texture object node. ...

GAS: Double attributes not shown GameplayDebugger

UE - Gameplay - Gameplay Ability System - Aug 27, 2025

Context The Gameplay Ability System lets devs specify numerical attribute properties in UAttributeSet subclasses. Although the preferred attribute property type is FGameplayAttributeData, GAS has l ...

Geometry Collection's Chaos Cache Static Pose Scrubbing broken in 5.6 due to Custom Renderer GeometryCollectionRootProxyRenderer

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

Geometry Collection's Chaos Cache Static Pose Scrubbing broken in 5.6 due to Custom Renderer GeometryCollectionRootProxyRenderer. The licensee has provided his analysis: In 5.6, when creating a Geo ...

Adding pin to CR node causes crash if input variable is assigned to one of the array element

UE - Anim - Rigging - Control Rig - Aug 22, 2025

When a node has a variable assigned to one of its pins. You will get a crash every time you add a pin. I am sure this goes for all nodes with with the "add pin" functionality [Link Removed] ...