Pathtracer rendering artifacts with foliage culling

As shown in the video. Enabled foliage culling (instancedStaicMeshes.Culling - 1) which is default setting in unreal, introduces some artifacts. To me it looks like normals randomly flip on the meshes. Disabling culling fixes the issue for pathtracer.

I only noticed this issue with pathtracing so far. (UE 5.0.1)