Crash on Mac on exit.

Media Framework - Aug 17, 2020

A licensee reported trouble with a crash on exit on Mac. They discovered that the file AvfMediaPlayer.cpp, on the function Open there is this piece of code:// Force the AV player to not be able to ...

OSS Steam: SteamSocket listen connections do not work after poll group changes

UE - Online - Oct 25, 2021

In 4.27 the logic in SteamSocket.cpp which is part of the SteamSockets plugin was changed to use Poll Groups instead of a removed API function that checked all children of a listen socket. However,  ...

Switchboard Unable to Launch Multi-User Slate Server in Launcher Builds

UE - Virtual Production - Tools - Switchboard - Jan 14, 2023

Switchboard is unable to launch the Multi-User Slate Server in launcher builds.  This is because the default install location has "Program Files and "Epic Games" in the path (aka folders with spaces ...

Animation attributes - user defined structs containing types defined in plugins cannot be registered

UE - Anim - Runtime - Dec 18, 2023

This issue is caused by us forcing user defined structs to be loaded as part of AttributeTypes::Initialize.  That is called after at the ObjectSystemReady run phase during engine initialization howe ...

Hierarchical and normal Instanced Static Mesh Components do not maintain PerInstanceRandom values when transforms are modified

UE - Graphics Features - Nov 6, 2017

When using PerInstanceRandom in a material that is applied to a Hierarchical or normal Instanced Static Mesh component, there are issues of the value resetting when certain transform operations are ...

Bug - Animations and Keep State Fail when scrubbing backward.

UE - Anim - Sequencer - Jan 30, 2020

If you scrub past an animation with keep state, and scrub into an animation with defaults everything is fine. When you scrub back to the animation with keep state, the animation breaks, until there ...

Navmesh seems to have buggy behavior when interacting with HISMCs that programmatically set mesh via SetStaticMesh.

UE - AI - Mar 6, 2020

Both versions works correctly if HISMC is pre-placed (generated in ConstructionScript). Only when generated dynamically does it fails. The Navmesh isn't being updated after SetStaticMesh and AddInst ...

Color space transform in the UI composition is incorrect on DX12 HDR (r.HDR.UI.CompositeMode=1)

UE - Graphics Features - Jun 11, 2021

Color space conversion in the UI composition is incorrect on DX12 HDR. In the main() function In CompositeUIPixelShader.usf, you can see the following color space transform.// sRGB -> RRT -> ODT ...

USplineComponent::GetDistanceAlongSplineAtSplineInputKey returns incorrect result when input keys are not sequential

UE - Editor - Workflow Systems - May 18, 2022

USplineComponent::GetDistanceAlongSplineAtInputKey() returns the wrong value when the input keys are not sequential because it interprets the input key argument as the spline point index. Thus if th ...