Hi i currently use OF 4.5. as server and Gajim as client.
When the client goes offline the session becomes Invalid session/connection state.
Then when the client logins again it will get a new session.
Furthermore if i click on the red x button to remove the invalid session, the session will not be removed and stays in the list, but the admin console tells me that the session was removed.
In the logs i often get this message too:
org.jivesoftware.openfire.SessionManager - Not removing detached session 'XMMPDOMAIN/aim3dy7l1' (aim3dy7l1) that appears to have been replaced by another session.