Unreal Engine Issues and Bug Tracker

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Latest Bugs

Deadlock while cooking groom bindings

UE - Anim - Mutable

Hi, we are experiencing random deadlocks while cooking groom bindings. We have integrated 5.8 mutable into 5.6 and are still experimenting tho...

Crash in GC - FSharedStruct reachability race condition

This Jira was created from the linked EPS case: =============================================== This issue is caused by FSharedStruct batch...

Regarding TObjectPtr performance regression

UE - CoreTech - UObject

This is from the linked EPS case: ============================== When 5.0 first introduced TObjectPtr, the guidance was that it would compi...

Navigation data contained entirely within a Level Instance is not registered at runtime (PIE / standalone / packaged) in a World Partition persistent level

UE - AI - Navigation

A licensee is composing independently-authored levels into a single World Partition persistent level by placing each as a Level Instance. NavM...

WorldPartition RuntimeHashSet: non-deterministic URuntimePartitionPersistent UObject name causes unstable Cooked output (RuntimePartition:DebugColor)

UE - World Creation - Worldbuilding Tools - HLOD

During deterministic Cook / Package validation, the Cooked output of a WorldPartition map was found to vary non-deterministically between Cook...

Latest Fixes

World is initialized twice when opened through the Content Browser

UE - World Creation - Worldbuilding Tools

When opening a Level from the Content Browser, the world gets initialized twice. This initialization process can be quite long, especially for...

Parameter metadata not accessible if modified in Material Instance and then converted to CustomPrimitiveData

UE - Rendering - Architecture - Materials

There’s a potential issue with some changes we made to UMaterialInstance::GetParameterValue (https://github.com/EpicGames/UnrealEngine/commit/...

Rare crash in FWidgetAnimationState::OnStopped

UE - Anim - Sequencer

The FWidgetAnimationState::OnStopped delegate is getting created when the widget anim state is being destroyed and then queued to be executed ...

Mutable Dataless Generation - Regenerate Imported Models Crash

UE - Anim - Mutable

Crash when working with Dataless Mutable content. When selecting meshes in the instance, there is a crash in RegenerateImportedModels....

Nanite Skeletal Mesh ignores Hidden Material Section flag

UE - Rendering - Graphics Features - Nanite

Unlike non-Nanite Skeletal Meshes, Nanite-enabled Skeletal Meshes do not correctly respond to the Show flag passed via ShowMaterialSection(). ...