1. Create user CSV without password column;
2. Upload users into moodle. Important settings:
Upload Type: Add new users
New user password: Create password if necessary
(other settings as necessary)
3. Upload users. Results page will say under password column "Generated in cron"
4. Run the cron script
Error message: "Scheduled task failed: Send new user passwords,Authentication plugin {$a} not found."

The problem lies within the SQL in /lib/classes/task/send_new_user_passwords_task.php: 51
The "auth" field needs to be included for the functions that follow.