Indirect lighting samples incorrect if duplicated levels placed in same persistent level

UE - Graphics Features - Aug 29, 2017

Indirect lighting samples were not made correctly when building lighting with umap duplicated via the content browser and registering both source and destination as sublevels in one map. ...

Copying a grouped MaterialInstanceParameterDetail property that has spaces on it's name does not enclose it in double quotes, and later pasting won't work as expected

UE - Rendering - Architecture - Materials - Aug 24, 2025

Copying a grouped MaterialInstanceParameterDetail property that has spaces on it's name does not enclose it in double quotes, and later pasting won't work as expected. The licensee noticed this in a ...

Regression - Nested scene component subobjects are no longer being registered when the owning scene component is added to an existing Actor instance as an instanced component.

UE - Gameplay - Components - Nov 16, 2016

This is a regression that was introduced with changes made to address issues with native vs. non-native component registration at Blueprint construction time ([Link Removed]). Prior to those change ...

Editor 'Build All Levels' discards Volumetrics Lightmaps in persistent level

UE - Rendering - Features - May 14, 2025

Building the level or lightmaps can clear the volumetric lightmap. In 5.5, this requires you to perform a full build, or a lighting only build with a BSP brush in the scene. In 5.6, all level build ...

Mobile Previewer: Safe Zone Invalid Until Window Resize

UE - Platform - Mobile - Systems - Jul 12, 2021

When the Mobile Previewer loads, the Safe Zone widget is not working properly at startup, and requires a window resize to update to the correct Safe Zone. ...

IOS crash disabling idle timer when closing the app

UE - Platform - Mobile - Apr 29, 2020

Licensee report of crash during shutdown due to setting [UIApplication sharedApplication].idleTimerDisabledbeing from the Game thread. Grouped together with others items in [Link Removed] ...

Custom UVs don't store information properly in layered materials.

UE - Rendering - Architecture - Materials - May 9, 2022

[Link Removed] I have this set up so that FX artists can stack UV manipulations, so I don't want to just have all the UV manipulation in the layer with the base color, even though that does give me ...

After importing morph target: Ensure condition failed: Referencing SkeletalRenderGPUSkin.cpp

Tools - Sep 23, 2017

Hit handled ensure when dragging the slider in Morph Target PreviewLogOutputDevice: Error: Ensure condition failed: DynamicData->MorphTargetWeights.Num() == LODModel.MorphTargetVertexInfoBuffers.Get ...

Crash caused by a race condition in Nanite::DispatchBasePass()

UE - Rendering - Features - Nanite - Feb 25, 2026

Nanite::BuildShadingCommands() launches two asynchronous tasks: ShadingCommands.SetupTask ShadingCommands.BuildCommandsTask BuildCommandsTask is responsible for modifying ShadingCommands.Commands ...

ACineCameraAttachMount's "Target Actor" constraint does not work with Spawnables or Replaceables in Sequencer

UE - CAPT - Tools - Virtual Camera - Aug 12, 2025

Constraints (UTickableConstraint) are usually created throuh the "Animation" tab available in the Editor's "Animation Mode". When created through that interface while Sequencer is open, the internal ...