Unreal Engine Issues
Unreal Engine Issues
Sequencer.AllowPausedClock makes Audio/Platform-clock sequences evaluate at a negative time after any earlier game pause
UE - Audio - Sequencer - Oct 17, 20265.8 added Sequencer.AllowPausedClock (on by default) in FMovieSceneTimeController_ExternalClock::OnRequestCurrentTime (MovieSceneTimeController.cpp): PausedTime = Context.World()>RealTimeSeconds - ...
Crash when merging a file containing an Orbit Rig
TM - Tools - Oct 16, 2026Reported in SF [Link Removed] Scenes containing Orbit Rigs will cause crashes when attempting to Merge with other files. ...
Crash in Landscape Editor when clicking on Terrain Edit tools after undoing a Landscape swap
TM - Core - Oct 16, 2026Reported in SF [Link Removed] Twinmotion will crash when clicking on any of the Landscape Edit tools after replacing the Landscape and performing an undo operation This only appears to occur in th ...
Export: TXT (just textures) export constructs the whole exportable mesh
RS - Editor - Oct 16, 2026This has been there since the start. Because of the exporter design the textures are coupled to the mesh geometry so in order to export them the whole mesh is first prepared and then thrown away. ...
Deadlock in URigHierarchy
UE - ACT Character - Control Rig - Oct 12, 2026We are regularly hitting a deadlock on 5.8.3. We have one background worker evaluating an animation, holding the RigHierarchy's ElementsLock and waiting for the global GC lock And one Background w ...
Mass instanced skinned mesh sweep removes instances without freeing their ASTP tracks
UE - MVF Character - Animation - Oct 7, 2026When an entity stops being batched into an instanced skinned mesh component, the "Collect unwanted items & remove" sweep removes its instance, but never frees its ASTP track. Only ProcessRemovesForC ...
Mutable Material Switch node not working
UE - Runtime - Mutable - Oct 7, 2026When using the Material Switch node in Mutable (UE5.8), I do not seem to get pins to wire in my Materials to switch between. Other switch nodes like Mesh Switch seem to work fine. ...
Substrate: FPrimitiveViewRelevance::operator|= bitwise-ORs SubstrateUintPerPixel, inflating the per-pixel byte count and asserting under the blendable GBuffer
UE - Rendering - Features - Shading Models - Oct 6, 2026A crash can occur due to this check in Substrate.cpp when a material with 2 units and a material with 5 (20 bpp) uints are combined triggering :check(CurrentMaxBytesPerPixel <= PlatformSettingsBytes ...
[SSAM]Textures that are still compiling are all counted as UnknownRef
UE - Engine Scaling - Streaming - Oct 5, 2026In UE5.8, the texture scale fallback is no longer applied when SSAM is enabled. As a result, if a material cannot access its TextureStreamingData when it is loaded, its textures are treated as Unkno ...
FDebug::EnsureFailed will only broadcast OnHandleSystemEnsure 4 times.
UE - Core - Systems - Oct 5, 2026A licensee is reporting that OnHandleSystemEnsure will only be broadcasted for the first 4 ensures in the life of the process. This is hardcoded with MaxPreviousErrorsToTrack. The licensee is using ...