Koha documentation says:

    Note

    Superlibrarians will see modifications for any branch, other staff will
    only see modifications for patrons who belong to their logged in branch.

http://manual.koha-community.org/3.22/en/mangepatronedits.html

However non-superlibrarian staff *can* see patron modification requests from other branches.

To replicate:

1/ In opac, create a self registration request at branch A.
2/ Log in to staff client as non-superlibrarian staff member with 'modify patron' permissions, at branch B.
3/ Note that 'Patrons requesting modifications' on Staff Client Home page will show a request.
4/ Click on 'Patrons requesting modifications'. You will see the request from step 1/.