Hardware Lumen Surface Cache Artifacts on Nanite Geometry

UE - Graphics Features - Lumen - Sep 1, 2025

When using Hardware Lumen with Nanite-enabled meshes in UE 5.6+, black / dark surface cache artifacts appear that result in generally darker and unstable lighting. These artifacts are not immediatel ...

Chaos sometimes can not generate contact points while two dynamic convex hulls actually collide. It results in instability in the contact behavior​ - such as jittering, inconsistent contact forces, or unexpected collision responses.

UE - Simulation - Core - Dec 2, 2025

Context: Chaos Physics is able to use convex hulls to represent object collision geometry for queries and simulation. Problem: Chaos sometimes can not generate contact points while two dynamic conv ...

[HORDE] Workspace does not respect stream view if the paths within the stream change to a newer CL then that of the stream

UE - Foundation - Horde - Dec 9, 2025

For example, if you have the engine in a different stream and specify an exact CL to use on the import path, you then update that import path to a later change with a higher CL number than that of t ...

[MetaSounds] - Input Parameter Settings revert to the default after a MetaSound becomes virtual

UE - Audio - MetaSounds - Sep 23, 2022

On restarting from Virtualizing, any parameters set previously on a MetaSound are ignored and the MetaSound restarts with the default values. This does not behave this way with Sound Cues, in which ...

Play options menu vanishes sometimes

UE - Editor - Applied Usability - Oct 8, 2024

There seems to be something wrong with how we close menus and submenus as submenus are opened and closed based on mouse interaction. In particular, we seem to sometimes close the whole menu hierarch ...

Android Client unable to join VOIP Host Session

UE - Online - Aug 6, 2019

Android client is unable to join a VOIP Hosted Session. The following messaging occurs when the Client tries to join a found session on Android:LogInit: BSD_Android: I am localhost (127.0.0.1:0) L ...

Waking both of a constraint's rigidbodies re-enables collisions between constrained actors that were disabled by a Physics Constraint Actor

UE - Simulation - Physics - Solver - Apr 12, 2022

Waking both of a constraint's rigidbodies re-enables collisions that were disabled by the physics constraint You can also get this issue to occur by either shooting the two cubes around a bit, or by ...

Movement corrections occurring while standing still on rotating platforms

UE - Gameplay - Player Movement - Oct 5, 2022

When the player is controlling a Character actor, using the CharacterMovementComponent (CMC), unexpected movement corrections will occur while standing still on a movement base that is rotating. ...

Some Niagara FX does not show up in MovieSceneCapture when AgeUpdateMode is DesiredAgeNoSeek

UE - Niagara - Cinematics - Sep 17, 2024

CL23957356 changes how to calculate FrameOffset in FNiagaraSystemUpdateDesiredAgeExecutionToken::Execute(). After this change, DesiredAge + FrameOffset could be 0.0 for some a couple of initial fram ...

Crash when loading array of UStructs containing Instanced property

UE - Gameplay - Blueprint - Jan 26, 2022

The editor crashes with a failed assertion when opening a blueprint actor that contains a structure with instanced objects. ...