When using OpenLevel to transition to a level with WorldPartition enabled during PIE, the log outputs "Failed to load '/Game/MapName': Can't find file."

UE - World Creation - Worldbuilding Tools - May 31, 2022

Outputs warning logs when transitioning to the World Partition level with OpenLevel. This only occurs in PIE, not in Standalone or Package builds. In PIE, it appears that the package failed to load ...

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

UE - Simulation - Visual - 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 ...

Mobile Map loading times have increased from 4.12 to 4.13

UE - Platform - Mobile - Oct 4, 2016

The loading time from 4.12 to 4.13 on mobile devices seems to have increased quite a bit. My results: 4.12.5 Windows 7 - Launch On: Loading Level 2 - .51 Loading Level 3 - .74 Loading Level 1 - .73 ...

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 ...

Sequencer causes 3DWidget on BP vectors to snap to Actor when active

UE - Anim - Sequencer - Nov 15, 2025

When we have Vectors in BP with Show 3D Widget enabled, the Transform Widget would always snap back to the Actor after we move the 3D Widget in-world. [Link Removed] Removing the _DaySequenceActor ...

Open Formats: Interchange Import Runtime - Interchange ImportAssetAsync runtime GLB import — materials, textures, tangents, and shaders non-functional in packaged builds (6 issues, UE 5.7.4)

UE - Editor - Open File Formats - Apr 30, 2026

Description* We are using Interchange's `UInterchangeManager::ImportAssetAsync()` to import GLB files at runtime in a packaged (Shipping) application. The orchestration layer (`ImportInternal` in `In ...

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 - Verse Class Editor - 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 ...

The process may not return to the root node after the Wait Task is completed.

UE - AI - BehaviorTree - Sep 14, 2021

If the Wait Task is completed for the first frame, it may not return to the root node even after Finish. This can be avoided by increasing the wait time of the Wait Task (see CaseOK.mp4). When this ...