Since v 4.4.1 (at least) if a user logs out of their desktop and backin , ie: a reboot, openfire doesnt remove the user, ok, it does but it doesnt, and I’ve verified this using gajim on my linux desktop.
If I look in sessions that old session is not there, but user online, and gajim shows yourself in its list, up above all other contacts, even if you logout for overnight and back in next day, some 9 hours later, its still there even though it still shows no sessions for that user, the user list shows as online, only if I shutdown openfire and restart it, does it clear it.
This never happened in versions prior to 4.4, the stale checks would find that invalid 5 or so mins later and clear it
Also, gajim is the same version, no updates to it in sometime ( 2 years I think I last built mine) other reporting users use different versions.