Unreal Engine Issues
Unreal Engine Issues
Temporal blur artifacts on Geometry Cache Components in Blueprint actor
UE - Editor - Content Pipeline - Alembic - Jan 9, 2026When a Geometry Collection is in a Blueprint, attached to other components, it can render incorrect motion vectors at some angles. In the test project, any angle that is not a multiple of 45 will re ...
Inconsistent Behavior in TextureLODGroups when setting NumStreamedMips=0
UE - Rendering - Architecture - Jan 8, 2026A licensee has reported that it is not possible to disable texture streaming of a given TextureLODGroup by setting "NumStreamedMips=0" in their device profiles. Currently, using 0 results in the sam ...
OverrideVertexColor causes a crash on mobile renderer
UE - Platform - Mobile - Jan 8, 2026Setting Allow CPU Access on the mesh, or setting bSupportsManualVertexFetch=1 in Engine.ini, avoids the crash. ...
Global Weight of Slot Node is incorrect when fetched after using a Pose Cache
UE - Anim - Runtime - Anim Blueprints - Jan 7, 2026When a montage slot node output is pushed to a Pose Cache and used in a Two-Way Blend, the value returned by GetSlotNodeGlobalWeight will be the current fractional value rather than the actual globa ...
FViewElementPDI::DrawLine calls for SDPG_World are not rendered in PIE or in Game
UE - Rendering - Architecture - RHI - Jan 7, 2026When View.Family->EngineShowFlags.CompositeEditorPrimitives is false in the function RenderEditorPrimitivesForDPG. This code picks which version of the batched lines to renderconst FBatchedElements ...
MultiProcessCook Shader Symbols fail to write when two workers race and try to write them at the same time
UE - Foundation - Data Pipeline - Cooker - Jan 4, 2026When shadersymbols are requested, cooking shaders writes the symbol files into {Project} /Saved/ShaderSymbols/<PlatformName>. These symbols are written by the function FShaderSymbolExport::Write ...
Virtual Memory leak when using specific rendering settings in the template project
UE - Rendering - Architecture - RHI - Dec 20, 2025When a project is run with these settings in a template project, untracked virtual memory increases. Cvars r.GBufferFormat 3 r.Lumen.TraceMeshSDFs 1 r.Lumen.TranslucencyReflections.FrontLayer.Enab ...
Skeletal Mesh BLAS updates when not animating
UE - Rendering - Architecture - RHI - Dec 19, 2025The BLAS for Skeletal Meshes that don't move, or tick get updated every frame even if the animation and skin cache aren't updated. This adds over 1ms to update time. The only exception is if the sk ...
Subobject ComponentClass overrides cause failing assertions due to UObject reconstruction on AsyncLoadingThread
UE - Framework - dSTM - Dec 19, 2025Context The blueprint editor allows you to override an actor component's class in derived blueprints (component details panel -> Component Class). [Image Removed] Problem When a blueprint and it ...
Reflections of Masked Materials incorrect with Lumen HWRT and Max Refraction Bounces > 0
UE - Graphics Features - Lumen - Dec 18, 2025Lumen HWRT Reflections of Masked Materials are incorrect when "r.Lumen.Reflections.HardwareRayTracing.Translucent.MaxRefractionBounces" is greater than 0. The same issue occurs if the Post-Process V ...