duplicate online users

On line 584 of the user.module file.

$authenticated_users = db_query('SELECT u.uid, u.name FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.timestamp >= %d AND s.uid > 0 ORDER BY s.timestamp DESC', $interval);

It is returning duplicate users. I put a DISTINCT after SELECT and it shows up with only one user entry per online user and it works fine now.