Unreal Engine Issues
Unreal Engine Issues
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 ...
MovieSceneAnimMixer: Force Root Lock suppression is editor-only, causing PIE vs cooked divergence
UE - ACT Character - Sequencer - Jul 13, 2026The anim mixer's skeletal animation eval task suppresses an anim sequence's Force Root Lock during pose evaluation so the root-motion extraction task (FAnimNextExtractRootMotionTask) can measure and ...
Crash in GC - FSharedStruct reachability race condition
UE - Core - Systems - Jul 13, 2026This Jira was created from the linked EPS case: =============================================== This issue is caused by FSharedStruct batching reachability requests to the same underlying FInstan ...
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 ...
Editor crashes in FAsyncLoadingThread2::ProcessLoadedPackagesFromGame when Level Blueprint references external actor
UE - Engine Scaling - Streaming - Level Instances - Jun 26, 2026Adding a reference to an external actor in the level blueprint causes the package for the actor to be put in the import table of the level. In some cases, the actor package can end up calling postlo ...
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. ...
Adjusting Vegetation Growth for Bushes in Media Mode alters their global size settings
TM - Tools - Jun 25, 2026Reported in SF [Link Removed] When making adjustments to the Vegetation growth Season parameter inside Media Mode, if a scene contains Bushes then any adjustments to the Vegetation growth will adju ...
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 ...