As Domain Admin I can not add a new policies via RSAT. My account is in these groups: Administrators, DC Backup Hosts, Domain Admins, Domain Users, Enterprise Admins, Group Policies Creator Owners, Schema Admins. What other group I need to create policies via RSAT?
I think Domain Admin should be enough, did you run a system health check from UCS web GUI ?
I had some issue some time ago with permissons wrong on sysvol