I also facing the same issue
I know I can resolve this issue just setting one session per host = no
But in log it says "session already active closing previous one" then why it not close previous session and start new session automatically
I using usermanager to authenticate and accounting for PPP users
Whenever net is down and up again in few minutes then user not authenticating due to session already active in usermanager
So every time when net is down and up again so I have to manually clear session from usermanager which user not authenticating
The problem with doing that is that it causes "fighting" between users when it happens that two users have the same MAC address.
This could happen when devices are "cloned" (backup made and then restored on another device).
Such practice could go on undetected for some time when you just allow it.