paths to profile forms are stored in the database... any user can replace a form with their own...

so if you copied a forum from one domain to another domain (ie a test site), then your profile forms would be pointing to the original domain forms...  now to be clear, they are paths, not urls, so actually moving a domain would show an error, but in your case, since the main site and the test site are on same server, the paths would exist...

so anytime you move a simple press install, you will have to reset the profile tabs so they revert back...  not a lot of users replace the profile forms, but some do and the capability is there...

I think that is the only path like that...  of course, other hard coded urls, like on forum - components - login and registration would need to be updated...  additionally, you might want to 'reset' a few things on the housekeeping form for caches and what not...