Crash when using StaticDuplicateObject with mismathced Source and Destination class types

UE - Core - Systems - Jun 19, 2025

Starting in Unreal Engine 5.4, StaticDuplicateObject internally switched to using Unversioned Property Serialization (UPS) for performance reasons. However, UPS assumes the source and destination ob ...

FMultiReaderSingleWriterGT isn't thread safe

UE - Foundation - Core - May 17, 2016

From https://udn.unrealengine.com/questions/292741/fmultireadersinglewritergt-isnt-thread-safe.html: I've found that FMultiReaderSingleWriterGT has at least 2 bugs: The one that caused a deadlock ...

VolumetricCloud crashes in orthographic view

UE - Rendering - Features - Feb 17, 2025

FVolumetricRenderTargetViewStateData structure for the orthographic view is not initialized and the structure has some uninitialized member variables. If uninitialized FVolumetricRenderTargetViewSta ...

Replicated components spawned by CreateComponentOnInstance are broken by object reuse

UE - Gameplay - Apr 5, 2023

When the gameplay framework component manager creates components as part of CreateComponentOnInstance, it passes in the requested class name as the literal name of the component instead of using the ...

AddLocalTransform node does not match scale behavior described in the node's documentation

UE - Gameplay - Blueprint - Jun 29, 2018

The comment for the AddLocalTransform node states "Change in transform of the component in its local reference frame. Scale is unchanged." However, when the node is used, the existing scale of the o ...

ChaosDestructionDemo packages cannot be created in 4.25.1

UE - Simulation - Physics - Jul 17, 2020

UMovieSceneSequenceTickManager does not consider settings of Fixed Frame Rate

zComponent - Archive - Jun 15, 2023

Due to CL-20816478 UMovieSceneSequenceTickManager now calculates DeltaTime per Group instead of using DeltaSeconds directly. As a result, the FixedTimeFramerate in the project settings is being igno ...

Interchange: Static analysis fix for interchange manager

UE - Editor - Open File Formats - Import and Export - Aug 1, 2024