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. ...

Random Number Generated in Constructor Returning Different Value on Begin Play

UE - Gameplay - Jan 13, 2016

When generating a random number using FMath::RandHelper() in the constructor of an actor, attempting to print that same number on BeginPlay returns a different value than the constructor. However, ...

Hot reloading changes to a struct causes data table assets to break

UE - Gameplay - Mar 28, 2017

If a data table asset is based on a custom struct, making changes to and hot reloading the struct will not update the data table in the editor. Restarting the editor will prevent the data table fro ...

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 ...

Behavior of reparenting Component on UE5 is different from UE4

UE - Gameplay - Blueprint Editor - Mar 29, 2022

In UE4, Reparenting the Child Component did not update it on the screen, but the Relative Transform was updated. However, UE5 now retains Relative Transform, so there are on-screen updates. This is ...

Virtual Heightfield Mesh crash using released Vertex Factory

UE - Rendering Architecture - Jul 25, 2023

When using VirtualHeightfieldMesh we see intermittent crashes in FDepthPassMeshProcessor::TryAddMeshBatch(). This can happen when FVirtualTextureProducerCollection::CallPendingCallbacks() is called ...

Viewport Renders Black when adding a Third Player using Splitscreen Multiplayer

UE - Graphics Features - Feb 24, 2016

As the title suggests, whenever you attempt to add a third player using splitscreen, whenever the third player is created the viewport renders black. This only occurs when the viewport is sized to a ...