Hi Pat_Begley !
The Path Tracer currently does not support Nanite meshes, and uses the fallback mesh instead.
To improve the quality of the fallback mesh, you can change the Fallback Relative Error parameter down to 0 in the mesh properties editor window.
Here’s the difference between a value of 1
And 0
We are working on making Nanite compatible with the Path Tracer, but have no ETA to give you for now.
Hope this helped !
Cheers,
Antoine