See exhibit A:
Much of the shape is in light, part is in shadow.
If you look at the line (region) between the region of light and the shadow you can see something odd.
Some facets are smooth shaded and some are not.
Exhibit B shows the render mesh:
The edges of the flat facets seem to lie along the edges of thin quads (tall/thin or wide/short) in the render mesh but there are many thin quads that don’t seem to be flat shaded.
I have instances of this problem all over my model. I am uploading the 3dm file but be warned that it’s big. It’s about 295 Mb.
Smooth shading facets was solved back in the teapot age of computer graphics. As I understand it: you take the vertex normals and interpolate between them. So I wonder of Rhino is, I dunno, creating parallel vertex normals or if there is a bug in cycles and it can’t draw teapots properly because, now that I think of it, my shape is very tea-potty and it’s not drawing properly.