This article describes the difference between Proxy Sessions and Sessions.
In the FortiProxy dashboard, there are 2 widgets for Proxy sessions and Sessions.
Proxy sessions: sessions on which Security Function(s) are applied e.g. WF, AV, Application Control.
Proxy sessions related to the max licensed sessions and can be checked by:
# diagnose wad license detail
Sessions: all sessions including proxy sessions and other sessions such as sessions in which Security Function(s) are NOT applied, sessions between FortiProxy and external server such as authentication server, sessions between admin and FortiProxy, etc.
It is possible to check sessions by the command:
# diagnose sys session list