Blueprint functions with nested structs referencing UDataAssets generate errors if root not passed by value.

UE - Framework - Blueprint - Aug 17, 2022

The source of the error appears to be a stray DefaultValue="None" that's contained within the inner "Test_Nested_TestContainer" split pin (copy/paste the node to notepad to see this). If you refresh ...

Global Invalidation causes CommonAnimatedSwitcher to flicker after animation completes

UE - Editor - UI Systems - UMG - Feb 19, 2025

The common animated switcher will currently flicker for one frame when its transition animation completes if global invalidation is enabled. This appears to be caused by a visibility change (HitTest ...

Static lights become stationary after toggling visiblity of level in packaged build

UE - Graphics Features - Jun 11, 2025

In 5.5, there is a regression with baked lighting where static lights become stationary lights when a level is hidden and then made visible again. This happens in packaged builds and shows up as sta ...

Delete Unused Variables deletes variables used in Child Blueprints

UE - Gameplay - Blueprint - Dec 30, 2014

[NickW] Should perform a search in children, at least warn if this will break children. — Delete Unused Variables deletes variables used in Child Blueprints. Note: Not only child blueprints. If ...

Collision is not updated on Slave Meshes when using "Set Master Pose Component"

OLD - Anim - Feb 17, 2016

Collision pose is not updated on Slave Meshes when using "Set Master Pose Component". This occurs with both Physics assets and Per-Poly collision This severely effects anybody making characters ou ...

Moving a water body causes engine to drop fps and spike ms

UE - Graphics Tools - Terrain - Water - Apr 26, 2022

Moving a water body lowers performance on the engine. The fps drop from 120 to 30 and ms spike from 8 to 30. This issue occurs in 5.0 Binary and 4.27 Binary on Windows. On Mac, FPS drop and ms spike ...

Merge Actors Tool Simplifies Nanite Meshes

UE - World Creation - Worldbuilding Tools - Merge Actor - May 19, 2023

Tried every combination of LOD Selection Type, Nanite enanbled/disabled, the only way it would seem to get the full number of triangles from the source mesh into the merged mesh is to disable Nanite ...

Input pins of BP node are not updated after a hot reload

UE - Gameplay - Blueprint - Apr 17, 2015

If a code defined function that takes in a parameter is called from blueprints, the BP node will show the input pin for the parameter. If the parameter list is changed after the node is created and ...

Data Layers: GetDataLayerInstanceFromAssetName differs between editor and non-editor

UE - World Creation - Worldbuilding Tools - Data Layers - Apr 9, 2024

From licensee: The function AWorldDataLayers::GetDataLayerInstanceFromAssetName() uses different names in #WITH_EDITOR and without editor builds: #WITH_EDITOR config calls DataLayerInstance->GetDa ...

Crash upon using marquee selection in Anim Graph while debugging

UE - Gameplay - Blueprint - Apr 20, 2016

A user reported a crash that occurs only in Debug Editor, related to the Anim Graph of an Animation Blueprint. The issue involves marquee selecting multiple nodes inside of a State Machine transitio ...