Laravel, sudenly changed the session to other users?

What kind of environment are you experiencing this on? Is this local or some kind of cloud hosting where load balancing could happen?

The issue could be that you have a load balancer in front of your backend. After you refresh, you get to another backend and create a new session. Check your session.php and try using the database driver (read https://laravel.com/docs/5.6/session#configuration)