Unreal Engine Issues
Unreal Engine Issues
Crash when merging Skeletal Mesh with incomplete LOD streaming
UE - Anim - Rigging - Skeletal Editor - Jul 24, 2026SummaryMerging a Skeletal Mesh whose LOD streaming has not completed crashes with an AccessViolation while the vertex copy reads the Null buffers of LODs that have not been streamed inRoot cause is ...
Two-sided property of materials saved to User Library not preserved
TM - Tools - Jul 22, 2026Materials with the two-sided property enabled do not retain this setting when saved to the user library, reverting to one-sided whenever applied to objects, making it impossible to save a material a ...
BlendSpace Loop Boundary Produces Inconsistent Sync Marker Data andTriggers an AnimSequence Follower Assertion
UE - Anim - Jul 22, 2026Summary In UE 5.7.4, when a looping BlendSpace with Match Sync Phases enabled plays as a SyncGroup Leader and crosses its loop boundary during a transition to an external AnimSequenceFollower in th ...
Overwriting an anim sequence may scale the play rate of the anim instead of modifying underlying frame rate
UE - CAPT - Tools - Take Recorder - Jul 21, 2026The frame rate for an anim sequence is not being changed as expected when its being overwritten / re-imported. ...
SetInputMode_GameOnly + windowed mode: Win+Arrow window snapping stops working after dragging window across monitors on multi-display setup
UE - Editor - UI Systems - Slate - Jul 15, 2026When SetInputMode_GameOnly is applied on a PlayerController and the application runs in windowed mode on a multi-monitor setup, the Windows OS shortcut Win+Arrow (window snapping) stops functioning ...
VSM shadows are missing for non-Nanite meshes in a PPV where Megalights is disabled, but Megalights is enabled in the project
UE - Rendering - Features - Jul 14, 2026In UE 5.8 r.Visibility.LocalLightPrimitiveInteraction mode 2 (enabled if MegaLights is disabled) was added and made the new default as a performance optimization. However, this causes shadows to d ...
Deadlock while cooking groom bindings
UE - Anim - Mutable - 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 ...
MovieSceneAnimMixer: Force Root Lock suppression is editor-only, causing PIE vs cooked divergence
UE - Anim - 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 - CoreTech - 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 - CoreTech - UObject - 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 ...