It seems that a login from a session don't terminate the session. Output of login after a system start.
[rave@mother ~]$ loginctl list-sessions SESSION UID USER SEAT c1 995 lightdm seat0 1 1000 rave seat0
2 sessions listed.
After a logout/login.
[rave@mother ~]$ loginctl list-sessions SESSION UID USER SEAT 1 1000 rave seat0 c2 995 lightdm seat0 2 1000 rave seat0
3 sessions listed.
The old session is well listed.
It seems that a login from a session don't terminate the session.
Output of login after a system start.
[rave@mother ~]$ loginctl list-sessions
SESSION UID USER SEAT
c1 995 lightdm seat0
1 1000 rave seat0
2 sessions listed.
After a logout/login.
[rave@mother ~]$ loginctl list-sessions
SESSION UID USER SEAT
1 1000 rave seat0
c2 995 lightdm seat0
2 1000 rave seat0
3 sessions listed.
The old session is well listed.