AIX7-00-001016 - The regular users default primary group must be staff (or equivalent) on AIX.
The /usr/lib/security/mkuser.default file contains the default primary groups for regular and admin users. Setting a system group as the regular users' primary group increases the risk that the regular users can access privileged resources.
Set the default primary groups for regular to be 'staff'. # chsec -f /etc/security/mkuser.default -s user -a pgrp=staff