Please see attached. When I import a mesh for per-pixel painting, it distorts my mesh, see images. Ignore the colors. See the corners. The corners are no longer straight. It appears the import is trying to smooth the mesh, but all smoothing options are turned off during import. I also uploaded an image of my import settings.
On an aside note, I opened the same mesh for PTEX painting and it seemed to import correctly, but the UV map it created was a complete wreck and unusable.
What am I doing wrong, please? I'm pulling my hair out.