Unreal Engine Issues
Unreal Engine Issues
Out-of-Bounds Access During Partial Updates of ISMC Per-Instance Custom Data
UE - Graphics Features - Jan 6, 2026When using instance custom data values, removing an instance and changing the number of custom data floats in sequence can cause an array-out-of-bounds crash. The underlying arrays are not resized ...
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 ...
Lumen Global Distance Field Trace Leaking due to Surface Cache Sampling
UE - Rendering - Graphics Features - Jan 12, 2026At specific distances from a thin wall, surfaces inside of a sealed chamber can receive indirect lighting from outside, leaking light into the chamber. This appears to be due to how SWRT handles sa ...
HISM flickering when any character is visible
UE - Rendering - Architecture - RHI - 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 ...
"Move to Level" of Landscape Tool leads component scale mismatch
UE - Graphics Tools - Terrain - Landscape - Feb 12, 2026In UE 5.7.2, when moving a Landscape Component to a sub-level using Landscape Mode > Manage > Move to Level, the proxy transform is not synchronized with the root Landscape when the KeepWorldTransfo ...
Skeletal mesh reimport via legacy import creates duplicate Mesh sockets
UE - Editor - Content Pipeline - Import and Export - Feb 25, 2026Reimporting a Skeletal Mesh via legacy import duplicates mesh sockets. The issue does not reproduce when using the Interchange pipeline. ...
STAT_StaticMeshTotalMemory increases after repeated loading and unloading of a level containing Nanite static meshes
UE - Rendering - Graphics Features - Nanite - Feb 26, 2026The issue appears to be caused by a mismatch in the value returned by GetResourceSizeBytes(EResourceSizeMode::Exclusive) between InitResources() and ReleaseResources(). At InitResources(), the repo ...
Swarm Coordinator is not distributing Lighting Builds
UE - Foundation - Core - Jul 20, 2015Swarm Coordinator in 4.8.1/2 is not distributing light builds across accessible agents. If you have and open a Coordinator included in the 4.7.6 build of the Engine, Coordinator is distributing cor ...
HydroErosion on landscape crashes on Linux
UE - Platform - Linux - Mar 13, 2015While on a Linux OS, the editor immediately crashes if the Hydro Erosion tool is used on a landscape. ...
'Directions are not Compatible' error on ForEachLoopWithBreak if split struct pin is disconnected from Enum type
UE - Gameplay - Blueprint - Mar 25, 2015'Directions are not Compatible' error on ForEachLoopWithBreak if split struct pin is disconnected from Enum type. Note: If the pins are reconstructed and the resplit, the error is fixed. ...