Packed Level Actors will create ISMs with inverted normals when a portion of static meshes have negative scales. This is apparent with two-sided materials.

UE - World Creation - Worldbuilding Tools - Feb 17, 2025

Packed level actors will create ISM instances with inverted normals when the selection of meshes used to create the packed level actor contains a subset of meshes with negative scales. This is the ...

Mutable constant texture variable with ClipUV mask only works with new experimental dynamic variable is connected as well

UE - Anim - Mutable - Sep 22, 2025

We are attempting to use Mutable in 5.6.1 and have encountered an issue which we are not sure how to resolve. The issue occurs when using the ClipWithUVMask node. In short we have a customizable o ...

LIVE: Setting sg.EffectsQuality between values will reset Destructible meshes if they have fractured

UE - Simulation - Physics - Destruction - Nov 14, 2014

DESCRIPTION: Using the command line sg.EffectsQuality and setting a value will reset a destructible mesh if it has already been fractured. AH Post: https://answers.unrealengine.com/questions/12850 ...

C# UHT fails to recognize delegates declared in another class's namespace

UE - Core - Cpp Tools - UnrealHeaderTool - Dec 14, 2022

Repro Rate: 3/3 This issue occurs in the live build //UE5/Release-5.1 at CL 23058290. This issue has also been regression tested against //UE5/Release-5.0 at CL 20979098 and is confirmed to be a r ...

Crash when duplicating component with Instanced property initialized with CreateDefaultSubobject

UE - Framework - Feb 2, 2024

An editor crash can be observed when copy-pasting an actor with an actor component with an instanced object property when set to a non-default value. Detailed steps to reproduce are provided below. ...

Sequencer: Camera Lock Breaks After Closing Sequencer and Re-entering PIE

UE - Anim - Sequencer - Oct 9, 2025

Viewport camera lock in Sequencer fails to persist correctly after running PIE with Sequencer open, then closing Sequencer and running PIE again. The issue consistently reproduces using the attached ...

Skeletal Meshes have physics collisions lag

UE - Simulation - Physics - Oct 2, 2019

Skeletal mesh's physics collision lag behind the actual mesh. It didn't matter if there was just a root bone or multiple bones/constraints. This doesn't happen when using static meshes. The effect ...

[Interchange][gltf] Imported animation are all 1 frame long.

UE - Editor - Content Pipeline - Import and Export - Jan 27, 2025

All the imported animation only contain one frame. If the file contains in archive are imported in a gltf web viewer we can see animation are playing.  [Link Removed] [Link Removed] https://foru ...

Child widgets do not maintain the Enhanced Input bindings from their parents

UE - Gameplay - Input - Apr 9, 2025

Test content for this bug is in the /EnhancedInputTesting/UE_268605/EnhancedInput_UE268605 level in QAGame! When a widget blueprint is created with Enhanced Input bindings in the event graph, whe ...

ARKit GetCurrentFrame crashes app

UE - Platform - XR - Aug 22, 2018

Using "GetCurrentFrame" crashes app. "The crash is due to the default constructor of FAppleARKitFrame being called by the above mentioned blueprint function. That constructor fails to initialize fi ...