StateTree: While editing State Parameters or exposed properties of a Condition/Task, an ensure() fires when editing inputs of a Property Function bound to an array element

UE - AI - StateTree - Mar 5, 2026

Consider an array property that can be edited in the StateTree editor. This can be a State Parameter or an exposed property of a Condition or Task, for example. Each element of the array can be boun ...

FBX Export - StaticMesh export to FBX crashes if UVElements has more channels than VertexInstanceUVs

UE - Editor - Open File Formats - FBX - Jan 22, 2026

As indicated in the repro steps, we have a StaticMesh asset that, for some reason, has a mismatch in their serialized bulk data where:MeshDescription->GetNumUVElementChannels() == 2FStaticMeshConstA ...

An imported file that resides within the project's folders gets a relative path. That path is not updated it you copy the uasset to another folder. That breaks the Reimporting functionality.

UE - Editor - Open File Formats - Import and Export - Aug 28, 2024

An imported file that resides within the project's folders gets a relative path. That path is not updated it you copy the uasset to another folder, so from the location of the new asset's the relati ...

Crash trying to convert skeletal mesh to Nanite

UE - Rendering - Features - Nanite - Mar 6, 2025

In SkeletalRenderNanite.cpp / FDynamicSkelMeshObjectDataNanite::UpdateBonesRemovedByLOD, bone indices are of type FBoneIndexType (defined as uint16 from BoneIndices.h), instead of int32. On line 18 ...

Recompiling an ABP that another ABP has a Property Access dependency on without recompiling/linking the other causes a crash

UE - Runtime - Anim BP - Oct 2, 2025

The crash comes from the pointers in FAnimSubsystem_PropertyAccess::Library::Indirections in the layer ABP from pointing to old/invalid functions and properties from the trash ABP_Manny, as they hav ...

Chaos Modular Vehicles Examples desynchronizes easily

UE - Runtime - Character - Feb 27, 2025

Chaos Modular Vehicles Examples does not replicate properly and it's easy to reach a state of desynchronization where the state stops being replicated and position/rotation of cars mismatch. As an ...

USD Export - crashes when sub level holds level instance

UE - Editor - Open File Formats - USD - Mar 27, 2026

The engine is crashing when the user tries to export from a persistent level with a sub level that contains a level instance. ...