LevelEditor: "Replace Actor" marks level as dirty even when using external actors

UE - World Creation - Worldbuilding Tools - Jul 15, 2024

When using external actors, adding/removing/replacing/editing an actor instance inside a level does not cause any modification to the Level package, which helps reduce contention for the map file on ...

Orientation Warping breaks incoming poses where bones are in component space

UE - Anim - Gameplay - Apr 17, 2025

The orientation warping node breaks incoming poses where bones are already in component space. This is because, in EvaluateSkeletalControl_AnyThread, we are repeatedly setting bone transforms direc ...

Root motion from montages does not get mirrored correctly

UE - Anim - Gameplay - Dec 2, 2022

A customer noticed that root motion did not mirror properly when using montages.   The issue is that the root motion mirroring code is only called from FAnimSync::TickAssetPlayerInstances .   Th ...

FTickTaskLevel::RescheduleForIntervalParallel Crash

UE - World Creation - Worldbuilding Tools - Oct 11, 2023

Short description from Licensee (attached UDN has more info):When streaming a level in and/or out (out especially in World Partition due to the bRequireFullVisibilityToRender variable usage) there i ...

Montage Editor calls NotifyEnds of AnimNotifyState even when paused

UE - Anim - Gameplay - Oct 13, 2023

In the Animation Montage Editor, NotifyEnd is unexpectedly called when a time marker is in the middle of an AnimNotifyState and the animation preview gets paused. Because the Animation Montage Edito ...

Sampling textures with bias in the path of a custom data pin causes derivative operations when avoidable

UE - Rendering Architecture - Materials - Apr 8, 2025

Materials that make use of the analytical derivatives path to avoid hardware derivatives can still generate derivative operations on texture samples when the shading model has a custom data pin and ...

Ambient occlusion causing ghosting for animations when viewport is resized on DX11

UE - Graphics Features - Feb 10, 2025

Tested regression against //UE5/Release-5.4 @ CL35576357 and the issue did not occur. This is a confirmed regression.[Image Removed] Jira Bot attaches conversation thread from Slack [Image Removed]D ...

Translucent materials in the PostMotionBlur pass can cause a flickering viewport artefact when using TAA

UE - Graphics Features - Feb 5, 2025

There appears to be a bug relating to rendering multiple windows that can trigger under unknown circumstances. It has been reported on rectangle lights in the forums and on PostMotionBlur materials ...

When breaking a level instance, foliage instances in the LevelInstance are placed in the wrong location

UE - World Creation - Worldbuilding Tools - Level Instances - Jul 8, 2023

Following code works as a work around. The code updates placement information of instances. TMap<UFoliageType*, TArray<const FFoliageInstancePlacementInfo*>> AInstancedFoliageActor::GetInstancesF ...

Unexpected behavior when Actor Parenting in the World Outliner of a WP map

UE - World Creation - Worldbuilding Tools - World Partition - Nov 23, 2021

Licensee reports the following in the UDN: There seems to be some other erratic behavior when using parenting in world outliner (i.e. drag and drop one actor on another one in world outliner).Since ...