Unreal Engine Issues

Lumen temporal flicker after leaving Editor open for 3+ days

Lumen GI has temporal flickering/noise after running the Editor for 3+ days. ...

Lumen doesn't handle Area Lights Reflection Occlusion well

Ghosting effect of fast moving objects in Lumen

Lumen doesn't use correct sky light settings when GI scalability changes from Low to High

When the Global Illumination scalability settings are changed in the editor from High to Medium, they primarily act on the r.Lumen.DiffuseIndirect.Allow and r.SkyLight.RealTimeReflectionCapture.  No ...

Lumen interior light leaking occurs with realistic sun Lux values (20k)

When a realistic sun Lux value of 20,000 for the sun directional light, interior light leaking is much more pronounced then when using the default directional light Lux value of 10 Lux. ...

Thin Translucent rendering output is different on UnrealEditor/PC and PS5 with Ray Tracing enabled

Reported from UDN With RT Translucency and Reflections enabled, Thin Translucent rendering is incorrect on PS5 in UE 5.3 ...

Screen Probes and Specular Firefly Flickering near screen edges

Lumen's rough specular indirect lighting buffer can have fireflies along the bottom and right edges of the screen. Also tested in //UE5/Main, CL: 35177423 ...

Memory leak when Lumen is disabled but r.MeshCardRepresentation=1

When Lumen is disabled, but the cvar "r.MeshCardRepresentation" is set to 1, Lumen will continuously enqueue object removal from the Lumen Scene, without ever emptying the array of primitives to rem ...

Lumen reflection distortion

Lumen reflections appear distorted depending on the camera orientation. ...

Lumen screen traces from hair cast noising moving shadows on faces

There is moving blotchy noise on the head and face from hair when Lumen HZB tracing hits hair.  CL 33258050 fixes the noise in the hair, but tracing still hits hair when it starts from surfaces like ...