The problem is due to this code snippet (since commit 17da397):
https://github.com/cassiopc/boca/blob/master/src/optionlower.php#L32-L35
Wouldn't it make more sense to prevent teams to update their password using the admin's UI? I mean, setting the "Allow password change: No" option in /boca/admin/user.php

Team users cannot change their password even if the admin user sets this option to "Yes".
Thanks!