Changing "Coordinate Light Map Index" When "Generate Lightmap UVs" Is Enabled In A Static Mesh Crashes Engine

Tools - Dec 31, 2019

When altering "Coordinate Light Map Index" in a static mesh when "Generate Lightmap UVs" is enabled in LOD 0 the engine will crash or "Coordinate Light Map Index" will be set to 0. A demonstration ...

SWorldPartitionEditorGrid2D causing editor to crash

UE - World Creation - Worldbuilding Tools - World Partition - Mar 13, 2023

"Favorite Levels" not persisting correctly when changed in the Editor

UE - Editor - Workflow Systems - Nov 21, 2023

In the Level Editor's "File" menu, there is a "Favorite Levels" list, which is persisted in the config file "EditorPerProjectUserSettings.ini" under section "[FavoriteFiles]". Manually editing this ...

"StaticFindFirstObject: Ambiguous object name" on delegates with timelines in packed level actors

UE - World Creation - Worldbuilding Tools - Level Instances - Jan 31, 2024

PropertySet : changes in instancedstruct are not detected by the watch

UE - Graphics Tools - Modeling Tools - GeometryScripting - Jan 24, 2025

Hi, I tried to use for a scriptable tool the watch property node for a struct. The objective for me was to offer to my user a view of a struct in the scriptable tool and have these modifications b ...

[AI] Navmesh tiles on different layers get removed while streaming out in WP Dynamic Modifiers Only navmesh

UE - AI - Navigation - Feb 6, 2025

 Streaming out the navmesh and streaming the area back into the world before the GC runs causes the navmesh streamed back into the world to only have navmesh tiles on a layer with tiles that would b ...

Editor crash while saving asset during cook operation

UE - Foundation - Data Pipeline - Cooker - Apr 2, 2025

It is possible to experience an editor crash in 5.5.4 when the cook process generates a warning that references an asset while the editor is saving. It seems that during a save operation, the code t ...

Assertion failed in FNetGUIDCache::CleanReferences during seamless travel after reloading primary asset package

UE - Networking - May 7, 2025

Following this sequence of events, the ObjectLookup and NetGUIDLookup on the server's PackageMapClient will end up in a bad state. In the ObjectLookup Map, the primary asset's package will be mapped ...

Saving Behavior Tree with Blueprint task inheriting from native class invalidates Blackboard key when BP contains a function

UE - AI - Jul 8, 2025

A regression introduced in UE 5.6 causes Blackboard key selectors in Blueprint tasks to become invalid when the Blueprint inherits from a native subclass of UBTTask_MoveTo (or UBTTask_BlackboardBase ...

BlueprintNativeEvent in Component Subclass does not show up in BP with the component

UE - Gameplay - Blueprint - Apr 20, 2015

If a function is marked as BlueprintNativeEvent inside of a class that inherits from a component (Scene component, Actor component, etc) then the function cannot be called in a blueprint with the co ...