Unreal Engine Issues
Unreal Engine Issues
USceneComponent::AttachToComponent may not be called on client depending on replication order
UE - Networking - Jan 13, 2026If the component being attached is received first, OnRep_AttachParent will set bNetUpdateAttachment to true, so USceneComponent::PostRepNotifies will call AttachToComponent. If the attach parent is ...
HISM flickering when any character is visible
UE - Graphics Features - Jan 12, 2026On an NVIDIA GPU, Instanced Static Meshes can flicker when a Groom card or mesh LOD is visible. This appears related to an issue rendering the ISM into the Scene Depth. At the end of the Prepass, t ...
Temporal blur artifacts on Geometry Cache Components in Blueprint actor
UE - Graphics Features - 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 ...
HDRIs do not appear in exported Presentations
TM - Core - Jan 7, 2026Reported in SF [Link Removed] HDRI environments are not appearing in exported Presentations. Occurs for both Local and Cloud exports and across all HDRI types. Thumbnails for Cloud Presentations w ...
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 ...