Welcome to the forums Vlad.
A few searches came up with the following.
The Path Tracer in Unreal Engine does not support Nanite meshes, and instead uses the fallback mesh. To improve the quality of the fallback mesh, you can:
- Change the Fallback Relative Error parameter
Go to the mesh properties editor window and lower this parameter to 0. This will use more of the source mesh’s triangles.
- Use local screen traces
This workaround uses local screen traces instead of the full resolution mesh, which can make Nanite meshes look correct with fewer artifacts.