I didn't find any diffs in the MVS sections. The hardest is the admin/category file. MVS, Header Tags, SEO URLS and Add More Fields like being in the same places. If you look at the checkout_ files and compare them from the files in 2.3.3 you can see some changes, but I doubt that's what's causing the problem since I have tried using the files from the mvs package and still get the same errors.
Pretty sure its on the admin side.