Pose watches don't display correctly with compatible skeletons

UE - Runtime - Anim BP - Aug 19, 2022

"Hello, we've found a quirk with ABP's pose watch and compatible skeletons. Same setup as above. We have skeleton A as the base and skeleton B as a compatible skeleton. They both share similar hiera ...

Iris - large fast arrays serialize multiple elements when only one is dirtied

UE - Networking - Iris - Apr 8, 2025

This seems to be a result of how the changemask is handled for fast arrays. Because the changemask is a fixed set of bits (defined by IrisFastArrayChangeMaskBits), a single bit can represent multipl ...

The hierarchy of Actors in LevelInstances can break when using BPs as parent

UE - World Creation - Worldbuilding Tools - Level Instances - Feb 18, 2026

The hierarchy of a LevelInstance actors (Outliner) will break when cooking. The source is the call to AActor::RerunConstructionScripts in FWorldPartitionLevelHelper::MoveExternalActorsToLevel. The ...

When typing Korean in Slate using FTextInputMethodContext, characters outside a specific range are not entered

UE - AI Workflows - UI Systems - Slate - Apr 7, 2026

Descriptions After getting the below message LogTextStoreACP: Verbose: GetTextExt - From 33 to 34 A line break past that range is inserted. However, when typing Korean, the correct range is not s ...

Crash when adding multiple collision types to a mesh

Tools - Jan 27, 2017

Adding various collision types to a single mesh will cause it to hard crash the editor. No Crash Reporter window will open. Note that this happens with the user's mesh, but I was not able to repro ...

USkinnedMeshComponent::FindClosestBone does not respect bRequirePhysicsAsset parameter

OLD - Anim - Mar 20, 2017

A licensee has reported that the USkinnedMeshComponent::FindClosestBone function does not respect the bRequiresPhysicsAsset parameter, resulting in the bone returning bones that are not part of the ...

Mouse Events cannot be treated as Touch on Android Apps on Chromebook

UE - Platform - Mobile - Mar 18, 2019

A licensee reported an issue where mouse events are not able to be used as touch events on Android apps. This was specifically reported on and tested on Chromebooks. After working with Chris Babcock ...

Huge performance hit when recording a demo (demorec)

UE - Networking - Jun 3, 2019

The current engine version (4.22) seems to suffer a huge performance hit when using the demo recording (demorec) feature. This issue is present in both the editor and the packaged game (developer bu ...

Deprecated components can still be added via the Add Component button

UE - Gameplay - Blueprint Editor - Oct 19, 2021

The UDN has a possible fix for this issue in the Component Type Registry You can use the following as a test C++ class: #pragma once #include "CoreMinimal.h" #include "Components/ActorComp ...

UInstancedStaticMeshComponentRemoveInstances crashes if called with an empty array

This looks like it can be fixed with an early-out when the passed array of indices is empty. Log:[2024.01.03-16.38.36:091][291]LogOutputDevice: Warning: Script Stack (1 frames) : /Game/BP_Crashy.B ...