Cloth environment collisions with APEX clothing is not thread safe.

UE - Simulation - Physics - Character - Jan 17, 2017

This looks like a thread safety bug that's been in the clothing system for a very long time. Essentially a skeletal mesh component does a transform update and attempts to update the collisions of a ...

With "Use Default Sample Rate" disabled, animations with 24fps get resampled to 30fps

Tools - May 30, 2017

With "Use Default Sample Rate" disabled, animations under 30fps get resampled to 30fps ...

User project crashes after changing struct

UE - Gameplay - Blueprint - Aug 10, 2017

Sequencer 3D Trajectories run very slow on deep hierarchies

UE - Anim - Sequencer - Aug 27, 2018

Using a Level Sequence with deep hierarchies causes the FPS to drop to low numbers when they are all selected within the Sequence. This is a regression from 4.19.2 (CL-4033788). This issue was repo ...

Float value of AIDataProvider_QueryParams is cast faild

UE - AI - Oct 9, 2018

IntValue and BoolValue is always indefinite value in UAIDataProvider_QueryParams::BindData(). Attach the result of Watch in VS. ...

GenerateVisibileRayTracingMeshCommands Severely Reduces Foliage Performance Even if no RayTracing is Used

UE - Graphics Features - Lumen - Sep 18, 2019

GenerateVisibileRayTracingMeshCommands Severely Reduces Foliage Performance Even if no RayTracing is Used. Found in 4.23 CL# 8386587 and 4.24 CL# 8748719 ...

Text3d renders backwards.

UE - Rendering Architecture - RHI - Aug 10, 2020

When adding a Text3D actor (after placed as Child Component), into viewport the actor renders backward and not as expected. I was able to reproduce this issue in 4.25.3, but did not have this issue ...

Landscape smooth and flatten tools deform the terrain incorrectly

UE - Graphics Tools - Terrain - Landscape - May 25, 2022

The Landscape smooth and flatten tools can deform the landscape incorrectly causing chunks of the landscape to be removed (see attached image). ...

Curve Table Editor's "Add Key" functionality does not work and appears to not be implemented..

UE - Editor - Workflow Systems - Aug 5, 2024

Creating a new Curve Table asset, and then trying to use the right-click menu "Add Key" option does not do anything. FRealCurveModel still has the function, but it is left intentionally empty despit ...

Structured log automated decimal number tests fail in languages / cultures that use commas instead of periods

UE - Foundation - Jul 17, 2025

The following Localisation Tests in "Engine\Source\Runtime\Core\Tests\Logging\StructuredLogFormatTest.cpp:275" TestLoc(LOCTEXT("Float", " {Float} "), ANSITEXTVIEW(R"(128.25)")); TestLoc(LOCTEXT ...