Update! I exported the problem object as an .obj with `materials`, `smoothing`, and `normals` set to `off`. Imported the obj back into the scene and it worked! Just thought I'd give you the heads up.
Thank you!! I will try it tomorrow, just pulled an all-nighter. 6AM, sun's been up for a few.
The education version of Maya is severely buggy. A few hours ago I unhid a layer that I was resuming work on... It tries to autosave (even when turned off) then gives a prompt about the educational version-ness of the software, then promptly crashes. Happens every time I reload the file and try to unhide that particular layer, which had been working just fine for the longest time during which I didn't touch it. Luckily I've been saving paranoid-progressively since this last snafu.
I had done a lot of work on another layer so I imported the objects I'd worked on back to an old save file and it stopped crashing.
I have a few dozen shader networks, maybe that's why?
RE: UV Sets - I was layering textures.