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 ...

Particle Data Exports only work in the final simulation stage

UE - Niagara - Nov 30, 2020

Particle data will not be exported unless it is in the final simulation stage. ...

SWorldPartitionEditorGrid2D causing editor to crash

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

"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 ...

Blurry RVTs after camera jump

UE - Graphics Features - Aug 7, 2025

When using Runtime Virtual Textures (RVT) on landscape in UE 5.5+, nearby tiles may remain blurry (low-resolution mips) after launching PIE or making large camera jumps (e.g. via bookmarks or viewpo ...