ChaosWheeledVehicleMovementComponent is breaking the const CDO contract and changes to the instances are being applied to the CDO

UE - Simulation - Gameplay - Apr 28, 2025

As described by the licensee, the const CDO contract is being broken on ChaosWheeledVehicleMovementComponent. The issue the licensee is facing is that by spawning cars with different configurations, ...

The default values of a Struct variable in a Blueprint will return to the default values of the Struct on compile when all values are set to 0

UE - Gameplay - Blueprint - Jan 19, 2015

The default values of a Struct variable in a Blueprint will return to the default values of the Struct on compile when all values are set to 0. Possibly related to [Link Removed] Tested in 4.6.1 a ...

Landscape Splines in Partially Loaded World Partition Levels Can Cause Nanite Landscape Invalidation

UE - Graphics Tools - Terrain - Nov 7, 2025

Certain placements of landscape splines in world partition levels can cause Nanite landscape proxies to invalidate, and switch back to their non-nanite version. This happens when specific regions of ...

UPlacementSubsystem does not respect AssetFactories priorities, which is inconsistent with UEditorEngine::ActorFactories and makes it impossible to override placed actor type when dragging asset from Content Browser to Level Editor Viewport.

UE - Editor - Workflow Systems - Mar 30, 2026

Note: This issue was reproduced in UE 5.7, and it works correctly in UE 4.27. Prior to CL 24938100 (between UE 5.1 and 5.2), all existing factories were discovered and registered during engine init ...

RepNotify variables passed by reference to a function or macro that then change the value of the variable do not trigger the OnRep function on the Server

UE - Networking - Jul 1, 2015

RepNotify variables passed by reference to a function or macro that then change the value of the variable do not trigger the OnRep function on the Server. This is inconsistent with the behavior with ...

Matinee movie recording is broken in 4.10

Tools - Dec 18, 2015

When trying to record a movie from a matinee in 4.10, it can fail for a number of reasons: 1. The folder does not exist 2. The cinematic view modes do not take effect 3. Trying to record a streamin ...

Crash due to D3D device being lost. (Error: 0x887A0006 - 'HUNG')

UE - Graphics Features - Feb 22, 2017

This JIRA has been made to consolidate all "D3D device being lost. (Error: 0x887A0006 - 'HUNG')" crashes into one. Previous Jira tickets include:[Link Removed][Link Removed][Link Removed][Link Remo ...

Copying a destructible mesh in the viewport loses reference to assigned mesh in the details panel

UE - Simulation - Physics - Destruction - Nov 4, 2014

BRANCH: MAIN CHANGELIST: 2346079 PLATFORM: Windows DESCRIPTION: When copying a Destructible mesh in the viewport the Destructible Mesh component will not be shown for the copied mesh. The mesh can ...

Memory leak after exiting PIE

There appears to be a memory leak when you PIE and then exit PIE. Users are reporting that each time they PIE, their RAM usage jumps up, say, 10MB, then when you exit PIE, it only drops down 5MB. ...

Key precision problems on some short animations

Tools - Apr 5, 2016

Please see attached UE4_anim_interp_bug.fbx for a second example. This works as expected in 4.7 and 4.8 I've got a couple different users reporting this now. I suspected animation compression to ...