Crash caused by Buffer Overread in TBitArray operator < function

UE - Foundation - Core - Aug 29, 2018

A licensee has reported a crash that is caused by a Buffer Overread in TBitArray's operator < function. While the licensee did not provide reproduction steps, the crash is apparent from looking at t ...

AIController can't properly unpossess character

UE - AI - Nov 5, 2018

There seems to be a bug with the Possess\Unpossess events. Because if you change the last node in "PossessCharacter", which is created in PlayerController(called "PC"), to Unpossess the AI still con ...

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 ...

r.AllowOcclussionQueries causing "huge RenderQuery Result" wait time in VR

UE - Graphics Features - Dec 3, 2019

Running r.AllowOcclusionQueries 0 command seems to set bWait = true, causing large wait times Tested: 4.22.3 CL#7053642 ,   4.24P4 CL#10387632 , 4.25 CL#10479005 Link to the users video, which ...

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 ...

Merging Splines causes Engine to Crash in 5.1

UE - World Creation - Worldbuilding Tools - Merge Actor - Dec 15, 2022

Attempting to merge two spline actors causes the Engine to crash. This issue occurs with the Steps to Reproduce regardless if there are more branches added to the tree branch spline/enabled, and reg ...

LOD dithered fade-out transition does not work since UE5.4

UE - Rendering Architecture - Aug 7, 2024

When DitheredLODTransition is enabled for HierarchicalInstancedStaticMesh, in the previous version (5.1.1), dithering was applied during fade-in/fade-out, but in 5.4.3, dithering is not applied duri ...

Modifying Notify Properties no longer updates the NotifyName in Blueprints with custom GetNotifyName function.

UE - Anim - Gameplay - Feb 13, 2025

If after placing a notify on an anim sequence timeline you modify a property that is used in the GetNotifyName function of a blueprint notify in engine version previous to 5.5 (5.4.3 for example) th ...

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 ...