[Quartz] - The multiplier does not always respected on the Quartz Quantization Boundary

UE - Audio - May 13, 2022

Increasing the multiplier past a certain point causes sounds on a Quantization Boundary to struggle to play at the correct time. The repro above uses 1/32, but this also repros with other values. ...

XR Planar Reflections lag behind VR headset movement

UE - Platform - XR - Mar 24, 2023

Planar Reflections lag behind VR headset movement [Link Removed] Reporting that reflection captures lag because they happen before late update is applied. Includes an experimental patch that fi ...

The AABBTree spatial acceleration structure goes off-sync when physics substepping is enabled in a "low" framerate environment.

UE - Simulation - Physics - Mar 15, 2024

When you enable the physics substepping, if you run the console command p.Chaos.Solver.DebugDrawSpatialAccelerationStructure 1, you can see how does not follow the physical object. The user that rep ...

[Legacy][FBX] Animation curves are not added to the skeleton anymore

UE - Editor - Content Pipeline - FBX - Jan 17, 2025

FNiagaraScalabilityManager incorrectly reactivates a NiagaraComponent that was deactivated by runtime user code

UE - Niagara - Scalability - Oct 1, 2025

Context: The Niagara System is the primary tool to do visual effects inside Unreal. Niagara systems can be culled due to distance. Problem: Once a deactivated Niagara System is culled due to distan ...

Patterns On Landscape Spline Normals

UE - Graphics Tools - Terrain - Oct 31, 2025

On higher-density Landscapes, Landscape Splines can lead to patterned artifacts in the geometry normals. Also tested on //UE/Release-5.6, CL:45232827 ...

Constraint Binding ID is broken on attach track when subsequence asset is moved.

UE - Anim - Sequencer - Jan 14, 2026

Moving a level sequence asset that contains actors that are being referenced as a subsequence in an attach track causes the references to drop, even though the subsequence reference is correctly upd ...

Cached State Machine is re-initialized whenever cached pose is referenced

OLD - Anim - May 19, 2015

This may not be an expected use of state machines, but it is becoming a showstopper for a couple of users. These user's are caching their locomotion state machine and then using a second state mach ...

Outside of AnimBP's, Animation Sequences with negative Rate Scales do not animate

OLD - Anim - Mar 20, 2015

Animation Sequences with negative Rate Scales do not play outside of using them in Animation Blueprints...unless they are looping. UPDATE: A negative rate scale value also breaks Anim Montages. ht ...

Duplicating meshes in blueprint improperly place transform widget and initially does not appear in viewport

UE - Gameplay - Blueprint - Jun 24, 2015

If a mesh is duplicated within a blueprint components panel, it will be invisible in the viewport, the transform widget will incorrectly align itself and refrain from moving, and if the transform wi ...