ResavePackages commandlet (buildlighting) fails/asserts on reflection captures in non-visible sub-levels

UE - Rendering - Graphics Features - May 13, 2025

When building reflection captures through the ResavePackages commandlet, it frequently triggers an ensure inside of ReflectionEnvironmentCapture.cpp. If distributed shader builds start causing prob ...

Mover character flickers downward while crouched and moving every so often

UE - Gameplay - Player Movement - Mover - May 8, 2025

Repro Rate 5/5 Packaged onWindows - 10 - Enterprise - L3864 Processor: AMD Ryzen Threadripper PRO 3975WX 32-Cores 3.50 GHz RAM: 128 GB GPU: NVIDIA GeForce RTX 3080 GPU Driver Version: 572.83 ...

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 ...

ChaosWheeledVehicleMovementComponent is breaking the const CDO contract and changes to the instances are being applied to the CDO

UE - Simulation - Gameplay - Apr 28, 2025

As described by the licensee, the const CDO contract is being broken on ChaosWheeledVehicleMovementComponent. The issue the licensee is facing is that by spawning cars with different configurations, ...

Fatal error when creating listen server on an instance with a PendingNetGame

UE - Networking - Apr 28, 2025

This seems to occur because the PendingNetGame is not destroyed when the instance browses to the new level to start listening. In UEngine::LoadMap, UWorld::SetGameMode will create the game mode, pro ...

Fields with Maximum resolution are not affecting all leaves of a Geometry Collection

UE - Simulation - Visual - Apr 25, 2025

Fields with Maximum resolution are not affecting all leaves of a Geometry Collection on 5.4 and onwards. When calling GetRelevantParticleHandles() a Maximum Resolution field does return all particl ...

Skylighting on distant objects causes severe flickering with Lumen

UE - Rendering - Graphics Features - Lumen - Mar 31, 2025

Lighting on distant meshes flickers when using Lumen and Skylights. Turning Lumen off and lighting from the skylight is stable. Turning off Lumen screen traces also lowers the amount of flickering ...