When bulk uploading users with auth=POP3, Moodle forces password change for those users. Since password are managed by an external system, users are no longer able to login once the password has been updated. That creates a major workload fro Admins who need to upload users in bulk.
- use a password salted site, with Password Policy=on
- create a CVS user import file, with a password column and authtype POP3
- import the users
- check the forcepassword field in the profile or in the db user table, the field is set to on.