OK, don't really understand what that means if it works after I save them.
Depends on what the field type is. By default a field created after users exist has a stored value of NULL. Saving them may adjust that, which would adjust the sorting.
What is the solution to sorting them correctly? Can you help me fix this?
The SQL is behaving as expected; there's no PHP side sorting to it. Enable debug mode and you can find the query for the userlist at the bottom of the page something like the below. Run it directly in phpmyadmin and you should see the same results as you do on your userlist. You should see your sorting directly in the ORDER BY clause of the SQL. There's no fixing this beyond understanding how your information is stored and what to expect from it. You can of course specify your own ORDER BY clause in the SQL by using Advanced sorting mode.
Code:
SELECT DISTINCT ue.*, u.*, '' AS 'NA'
FROM jos_users u
JOIN jos_user_usergroup_map g
ON g.`user_id` = u.`id`
JOIN jos_comprofiler ue
ON ue.`id` = u.`id`
WHERE u.block = 0
AND ue.banned = 0
AND ue.approved = 1
AND ue.confirmed = 1
AND g.group_id IN (1, 6, 7, 2, 3, 4, 5, 10, 12, 8)
ORDER BY `username` ASC
LIMIT 0, 15
krileon
