Unreal Engine Issues
Unreal Engine Issues
Sequencer: Entity task Pre/Post callbacks are skipped despite ForcePrePostTask when a required component is absent
UE - ACT Character - Sequencer - Oct 13, 2026Tasks scheduled through the entity task builder with FTaskParams::ForcePrePostTask() are documented to run their PreTask and PostTask callbacks even when there is no work for the task body. This gua ...
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 ...
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 ...
UBA: crash related to BeyongTrust PGHook.dll and Detour for local jobs.
UE - Core - Cpp Tools - UnrealBuildAccelerator - Oct 9, 2026A license provided a log containing a UBA crash related to PGHook injecting itself when ISPC runs. ...
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 ...
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 ...
Mutable Chaos Cloth breaks when culling mesh affects mesh sections with cloth
UE - Runtime - Mutable - Sep 29, 2026Encountering an issue since we updated to UE5.8 where characters whose cloth mesh sections have vertices culled will cause mesh degradation in editor and crashes in packaged builds. There are two i ...
Particle Random Value is the same for all particles with a Niagara Mesh Renderer
UE - Rendering - Architecture - Niagara - Sep 28, 2026A material using the Particle Random Value node returns the same value for every particle drawn by a Niagara Mesh Renderer. Particle transforms are not affected, only the random value. This happens ...
[Niagara][5.8] Data Channel Read and Write register with an identical type hash when fx.Niagara.DataChannels.Enabled is set from ini, hitting checkf in FNiagaraTypeRegistry::RegisterTypeInternal
UE - Rendering - Architecture - Niagara - Sep 28, 2026Affects: 5.8 (verified on Release-5.8), Windows, EditorSummary Adding fx.Niagara.DataChannels.Enabled=true to an ini file makes the Niagara editor assert when a Data Channel Read is created. The sa ...
Light Function and Post Process domain material thumbnails show the default material
UE - Rendering - Architecture - Materials - Sep 25, 2026Since 5.8, materials whose Material Domain is Light Function or Post Process no longer preview correctly in the editor. They render as the default material (WorldGridMaterial) instead of the materia ...