Unreal Engine Issues
Unreal Engine Issues
[5.8] Cherry-pick CL 55798320: re-precache PSOs in ULandscapeComponent and UGroomComponent OnRegister (fixes bPSOPrecacheCalled ensure on re-register)
UE - Rendering - RHI - Oct 21, 2026In 5.8, UPrimitiveComponent::OnUnregister resets FPSOPrecacheComponentData, which clears bPSOPrecacheCalled (regression from CL 48140040). ULandscapeComponent and UGroomComponent only call PrecacheP ...
Auto Size in Sequencer not working on MovieSceneSkeletalAnimationSection
UE - ACT Character - Sequencer - Oct 20, 2026My understanding of the Auto Size feature on sections in Sequencer is that I should be able to auto size a section based on its contents. For example, if pressing auto size on an animation clip, it ...
[UE 5.8][MediaViewer] Crash when switching Level Editor viewport type to Cinematic Viewport
UE - CAPT - Tools - Media Viewer - Oct 19, 2026POST LINK: https://forums.unrealengine.com/t/ue-5-8-mediaviewer-crash-when-switching-level-editor-viewport-type-to-cinematic-viewport/2747407 POST BODY:Summary The editor crashes when Media Viewer ...
Sequencer.AllowPausedClock makes Audio/Platform-clock sequences evaluate at a negative time after any earlier game pause
UE - ACT Character - Sequencer - Oct 17, 20265.8 added Sequencer.AllowPausedClock (on by default) in FMovieSceneTimeController_ExternalClock::OnRequestCurrentTime (MovieSceneTimeController.cpp): PausedTime = Context.World()>RealTimeSeconds - ...
Water: Data race calling MarkOwningWaterZoneForRebuild from FWaterBodyInfoMeshSceneProxy constructor during concurrent render state creation
UE - Graphics Tools - Terrain - Water - Oct 14, 2026Summary The FWaterBodyInfoMeshSceneProxy constructor (WaterBodyInfoMeshComponent.cpp) calls UWaterBodyComponent::MarkOwningWaterZoneForRebuild(). The proxy is created from CreateRenderState_Concurren ...
Water: WaterZone GPU data packed densely in FWaterViewExtension::UpdateGPUBuffers but indexed by sparse WaterZoneIndex, causing water to disappear
UE - Graphics Tools - Terrain - Water - Oct 14, 2026Summary Water can sporadically disappear in World Partition maps that have multiple spatially loaded AWaterZone actors. FWaterViewExtension::UpdateGPUBuffers() builds the WaterZoneData and WaterZone ...
[Landscape] weightmap layer allocations leak into left/top/top-left neighbor components
UE - Graphics Tools - Terrain - Landscape - Oct 13, 2026In 5.8, weightmap layer allocations of a landscape component leak into its left, top and top-left neighbor components when Edit Layers are merged. Neighbors end up with layers that were never painte ...
Sequencer custom task scheduler hangs with more than 512 tasks (TDynamicSparseBitSet::IsBitSet and operator|=)
UE - ACT Character - Sequencer - Oct 12, 2026With Sequencer.CustomTaskScheduling enabled, a task graph with more than 512 tasks can hang FEntitySystemScheduler::ExecuteTasks. Reported by a licensee, they hit it with a 528 task graph under Clan ...
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. ...
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 ...