Child actor components fail to attach in cooked builds when mobility is set to movable and end up at the origin

UE - Gameplay - Oct 21, 2025

Context: A Child Actor Component allows an actor in Unreal Engine to contain another actor as its child (component). Problem: The problem is inconsistent handling of child actor component mobility ...

When moving actors to the current level, their label is reset and displayed incorrectly on the Scene Outliner until the next time it is refreshed

UE - Editor - Workflow Systems - Jul 14, 2025

This is a regression, it worked correctly up to UE 5.4, but repros on UE 5.5 and 5.6. Also, this seems related to [Link Removed] ...

Geometry Collection (GC) fragments are affecting the Navmesh in wrong positions

UE - Simulation - Physics - Destruction - Dec 6, 2024

Geometry Collection (GC) fragments are affecting the Navmesh in wrong positions and the identified cause is wrong indexing. Once a GC breaks, it's fragments, when big enough, are creating islands in ...

When used with First Loop Start Frame Offset and Use Animation Blueprint, the character will alternate between the specified animation and the reference pose

UE - Anim - Anim in Engine - Jan 30, 2023

If you use StartFrameOffset set to 1 or higher in conjunction with the Use Animation Blueprint, the character's animation will be rough towards the end of the section. Specifically, it seems that th ...

Paper2D performance regression due to TArray resizing

UE - Graphics Features - Aug 16, 2019

We've noticed after upgrading our heavy Paper2D project to 4.22 that tilemap performance has been massively degraded compared to previous versions. After some digging we found out that it's due to a ...

When move selected foliage to level, Foliage can not move to level.

UE - World Creation - Worldbuilding Tools - Foliage - Jul 18, 2017

With 4.15, I can move Foliage to "Sublevel B", but I can not move it with 4.16. It seems to be affected by the update in 4.16 (New: When moving a foliage asset to a new level, you will now be prompt ...

FViewElementPDI::DrawLine calls for SDPG_World are not rendered in PIE or in Game

UE - Rendering Architecture - RHI - Jan 7, 2026

When View.Family->EngineShowFlags.CompositeEditorPrimitives is false in the function RenderEditorPrimitivesForDPG. This code picks which version of the batched lines to renderconst FBatchedElements ...

Crash on map change with non-null values for GPropertyColorationClass and request customizable property coloration color

UE - Editor - Workflow Systems - Aug 7, 2023

This was found by a customer through a UDN, and they offered the fix for it, as well. The basic steps to reproduce the crash are as follows:call GEditor->SetPropertyColorationTarget(...) somewhere i ...

Failed to build in Github UE4.27.0.

UE - Simulation - Physics - Aug 30, 2021

Failed to build UE4.27.0 with Win64/Development Editor.  Can avoid this error that excluding the project from build configuration. (Solution UE4->Properties->Configuration Properties->Configuratio ...

Force front x imported asset incorrectly display axis for thumbnail and default editor camera

UE - Editor - Content Pipeline - Import and Export - Apr 12, 2021

Thumbnail can be fix by (Quote from UDN) "adjusting OrbitYaw of the ThumbnailInfo for the +X-facing skeletal mesh" Persona Editors can be fix by (Quote from UDN) "setting SkeletalMesh->SetHasCustom ...