Crash on loading pre-4.20 cloth data when compute skin cache is enabled in 4.21

UE - Graphics Features - Mar 19, 2019

According to information from the licensee, the else clause was added to "FSkeletalMeshLODModel::(GetClothMappingData()" at CL 4437969 , but if it is the cloth data existing from 4.20 or earlier, it ...

Compile on load crashes for classes within an abstract class

UE - Gameplay - Blueprint Compiler - Feb 20, 2021

When compiling on load in -game, a blueprint class that inherits from a native class that is marked within and the class that it is within is abstract, a crash will occur when FBlueprintCompilationM ...

Incorrect volume bounds check in FTranslucentLightInjectionCollector::AddLightForInjection

UE - Graphics Features - Apr 8, 2025

The 'VolumeBounds' array in FTranslucentLightInjectionCollector::AddLightForInjection is accessed as a pointer instead of with 'VolumeCascadeIndex' and thus fails bounds checks for the outer volume. ...

Setting Slate.ShowBatching to 1 makes the entire screen green unexpectedly

UE - Editor - UI Systems - Slate - Jun 19, 2025

This issue may have occurred due to a refactoring of the related functionality during the engine update from version 5.4 to 5.5. The main reason is that the randomization of BatchColor doesn't work ...

Blueprints with Input action events are dirtied and upon being opened

UE - Gameplay - Blueprint Editor - Aug 10, 2017

Opening a blueprint that has an input event in it cause the blueprint to become dirtied and require compiling. Regression?: Yes This did not occur in 4.16.3-3561208+++UE4+Release-4.16 Versions tes ...

Level Sequence option "Allow Level Edits Only" causes Frame Rate drop when used

UE - Anim - Sequencer - Aug 15, 2017

When using the new option "Allow Level Edits Only" there is a drastic frame rate drop while playing the sequencer. This frame rate drops when only using this option. Versions Tested: 4.16.3 - CL: 3 ...

Property Table rendering very slow in 4.19 (regression)

Tools - Feb 8, 2018

Editor frame rate is very slow rendering the Property Table in 4.19.  This is a regression from 4.18 Showing frame-rate in the editor with the property editor open shows really high GPU time: [Ima ...

RecastNavMesh is not generated at loaded sublevel

UE - AI - Aug 16, 2018

RecastNavMesh is not generated at the sub level dynamically added in C ++ in 4.20. In 4.18, 4.19 it was generated normally. Probably, changes to the large number about NavMesh systems from 4.19 to ...

Certain combined Linear/Angular movements cause Client to freeze for several seconds

UE - Simulation - Physics - May 24, 2019

When using Replicated Movement, certain combined linear/angular movements cause the client to freeze for several seconds and then catch up to the server. This is a regression from 4.21.2 (CL-4753647 ...

RemoveAxisMapping() removes axis mappings of the same key regardless of Scale value

UE - Gameplay - Jun 26, 2019

When you remove an axis mapping using a specific key it will remove all mappings even if they have separate scales. The user found a fix that I verified that worked. In "InputSettings.cpp", which i ...