Unreal Engine Issues
Unreal Engine Issues
Deadlock while cooking groom bindings
UE - Runtime - Deformable - Jul 14, 2026Hi, we are experiencing random deadlocks while cooking groom bindings. We have integrated 5.8 mutable into 5.6 and are still experimenting those deadlocks which seem due to : UE_DEPRECATED(5.4, "Th ...
Cine Assembly - Cannot convert any bindings to spawnable
UE - CAPT - Tools - Shot Management - Jul 13, 2026You cannot change any binding type in bindings in Cinematic Assemblies, e.g., you cannot make something spawnable. ...
Mismatch in Landscape Layer Weights between Nanite and Non-Nanite Landscapes
UE - Rendering - Features - Nanite - Jul 13, 2026Repro project is available in the additional info URL to save repro time. Disabling Nanite on the landscape, or painting on it (which shows the non-Nanite version of the landscape) reverts the issu ...
Regarding TObjectPtr performance regression
UE - Core - Systems - Jul 13, 2026This is from the linked EPS case: ============================== When 5.0 first introduced TObjectPtr, the guidance was that it would compile down to raw pointer access in Shipping builds to ensu ...
Navigation data contained entirely within a Level Instance is not registered at runtime (PIE / standalone / packaged) in a World Partition persistent level
UE - Runtime - Character - Jul 13, 2026A licensee is composing independently-authored levels into a single World Partition persistent level by placing each as a Level Instance. NavMeshBoundsVolume / NavModifierVolume are placed inside ea ...
WorldPartition RuntimeHashSet: non-deterministic URuntimePartitionPersistent UObject name causes unstable Cooked output (RuntimePartition:DebugColor)
UE - Engine Scaling - Streaming - HLOD - Jul 9, 2026During deterministic Cook / Package validation, the Cooked output of a WorldPartition map was found to vary non-deterministically between Cook runs. Diff detected in the DiffOnly Cook log:Serialize ...
UserSceneTexture not working in Virtual Reality
UE - Platform - XR - Jun 25, 2026User reports that UserSceneTextures used in Post Process Materials are only correctly rendered inside the left eye in VR. ...
Parameter metadata not accessible if modified in Material Instance and then converted to CustomPrimitiveData
UE - Rendering - Architecture - Materials - Jun 24, 2026There’s a potential issue with some changes we made to UMaterialInstance::GetParameterValue (https://github.com/EpicGames/UnrealEngine/commit/8f2bebb008ba645f5938da844cd46b0925322b13). It seems as t ...
Custom expression additional outputs don't work when connected to World Position Offset
UE - Rendering - Architecture - Materials - Jun 24, 2026Custom expression additional outputs are considered (0,0,0) when connected to WPO. ...
Translucent meshes randomly flicker when using VSM
UE - Rendering - Features - Jun 23, 2026Flickering can occur on translucent materials, usually in the distance when there is at least one directional light and when using VSM. Flickering seems highly dependent on framerate and timing. L ...