Bone names of ~100 characters or longer crash the editor when baking to control rig

UE - Anim - Rigging - Control Rig - May 15, 2025

This is an issue with inconsistencies over rig names and how control names are generated. We expect that a control name will be appended with _CONTROL or _CURVE_CONTROL. But because URigHierarchy: ...

PIE Seamless Travel with a standalone level instance causes assert in UWorldPartition::BeginDestroy

UE - World Creation - Worldbuilding Tools - Level Instances - May 8, 2025

This check is hit on the server instance while it is performing garbage collection during the seamless travel. During this garbage collection, it will determine that the UWorldPartition object belon ...

Actor Channel failure occurs when quickly unloading and loading a streaming level

UE - Networking - May 8, 2025

With high enough latency, quickly unloading an reloading a streaming level with a replicated actor on the server can cause the actor channel on the client to fail to find this actor: UActorChannel:: ...

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 ...

AssetRegistry: In a packaged game ScanPathsSynchronous with bForceRescan=true will permanently forget about assets inside IOStore containers

UE - Foundation - Data Pipeline - May 7, 2025

This came up from several discussions on UDN and internal discussion. The root cause is that the AssetRegistry currently cannot discover packages inside IOStore containers, it relies on the seriali ...

DiffuseIndirect_Lumen_3 parameter missing and causing crash with Screen Space reflections and Lumen Async Compute

UE - Graphics Features - Lumen - May 3, 2025

When the Reflection Method is set to Screen Space and Lumen reflections async compute is enabled Unreal will crash because DiffuseIndirect_Lumen_3 parameter missing, due to how DenoiserOutputs are o ...

Blueprint compiler doesn't always initialize struct consts correctly

UE - Framework - Blueprint Compiler - May 1, 2025

Blueprints currently don't support unsigned 64 bit ints, but they do support signed 64 bits. If a Blueprint uses a native struct variable that contains a uint64 property, it incorrectly assigns that ...

UEditorValidatorBase::ValidateLoadedAsset() is not using the K2_ValidateLoadedAsset() output, effectively ignoring the Blueprint validation

UE - Framework - May 1, 2025

UEditorValidatorBase::ValidateLoadedAsset() is not using the K2_ValidateLoadedAsset() output, effectively ignoring the Blueprint validation. The K2Result is not used later in the function, and this ...

Transform Origin Scale on the Level Sequencce Actor's Instance Data can affect rotations

UE - Anim - Sequencer - Apr 30, 2025

Scale is used as part of the rotation calculation for transform multiplication, and it can have an effect in the sequence transform origins. It's expected that scale is completely ignored, and shou ...

Find in Blueprints: Default values in struct members are not returned

UE - Framework - Blueprint Editor - Apr 30, 2025

Context Find-in-Blueprints can be used to search the current, or all, blueprints. If you enter a simple string, it would return nodes, pins, pin default values and default values for BP Variables ( ...