Unreal Engine Issues
Unreal Engine Issues
WorldPartitionConvertCommandlet hits an assert when converting a persistent level that contains a sub-level with a landscape
UE - World Creation - Worldbuilding Tools - Nov 7, 2025Context: The Window tab allows a user to open the Levels window in order to add a sub-level to a persistent level. For Unreal Engine 5.0 and beyond, World Partition has made the Levels window obsole ...
Landscape Splines in Partially Loaded World Partition Levels Can Cause Nanite Landscape Invalidation
UE - Graphics Tools - Terrain - Nov 7, 2025Certain placements of landscape splines in world partition levels can cause Nanite landscape proxies to invalidate, and switch back to their non-nanite version. This happens when specific regions of ...
net.ReplicateCustomDeltaPropertiesInRepIndexOrder is not respect the cvar for the custom properties
UE - Networking - Nov 5, 2025In our project do not use iris and we use a subclass UExtendAbilitySystemComponent derived from UAbilitySystemComponent. In this subclass, there is a FastArray member variable named ExtendActivatabl ...
Static Mesh Contact Shadows still render when all LOD sections have Cast Shadows dissabled
UE - Graphics Features - Oct 30, 2025When the cast shadow checkbox is disabled for all sections that make up a static mesh the main shadow is no longer rendered but the contact shadow does not respect the instruction to disable shadows ...
Cloth Asset - Crash when importing morph targets into clothing
UE - Simulation - Visual - Oct 20, 2025The sim morph import has been broken after a change to make it work for cooked assets. Ticking the Import Sim Morph Targets checkbox crashes as soon as a skeletal mesh with morph target is specifie ...
Light Leak Issue in Modular Buildings (Lumen HZBTraversal)
UE - Graphics Features - Lumen - Oct 14, 2025Starting in Unreal Engine 5.6, disabling "r.Lumen.ScreenProbeGather.ScreenTraces.HZBTraversal" can lead to light leaking between adjacent or overlapping meshes. Also tested on Release-5.6, CL: 4523 ...
Material Instance Platform Stats don't update when Material Layer parameters are changed
UE - Rendering Architecture - Materials - Oct 14, 2025The instruction count appears to update properly if the whole asset editor is closed and reopened. ...
Skylight Leaking Tint in Reflection
UE - Graphics Features - Oct 10, 2025From 5.6 onwards, Skylight Leaking is much stronger in reflections than in the world. Also tested on //UE5/Release-5.6, CL 45232827 ...
APT copies only one CSV from GauntletTemp even if multiple perf sequences are run
UE - Platform - APT - Oct 8, 2025Reported by a licensee - separate CSVs from different perf sequences that are in one go are not picked up upon completion. ...
HZB Occlusion causes large stalls on the render thread
UE - Rendering Architecture - RHI - Oct 7, 2025HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...