not convinced it was really deactivated? did you just wait or confirm it was off…
asking because something is hijacking the ajax response there… ajax is used to save the profile information… it starts running, but then gets redirected to the main forum page and gives that back as the ajax response… obviously, the main forum page isnt a valid ajax resonse… so nothing is saved and while the profile button is actually doing what it is supposed, need to figure out what is interfering with the ajax…
so could be mod_security (lol, not really any good) or other…
have you done a temp theme change to default wp and see if working?
as an fyi, there are also other places where something is hijacking our ajax responses… so need to get to the bottom… it does not appear to be any plugin, so kind of leaves the theme… or something on the server…