First guess is you probably need to apply scale. In object mode, press Ctrl+a->Scale.
Second guess is duplicate vertices AKA double verts. In edit mode, press A to select all and then press M->By Distance.
yep looks like it was the scaling thing! such a weird problem. thanks for the help!
Non-uniform scale causes so many issues :D So much, in fact, that if something is acting weird, it's almost always the first thing to check :D
