On /cgi-bin/koha/members/moremember.pl?borrowernumber=51 when you click the + next to the patron search nothing happens. When you click the same thing on /cgi-bin/koha/members/members-home.pl it opens up some filters.
This was also reported on import_borrowers.pl, on bug 14690. It looks like a patch needs signoff there. Could it apply to this bug, too? I can confirm this continues to be an issue, at least in 3.18.8.
This is no longer valid on version 3.23. will set to Fixed :)