I'm having this problem too on a Mac Mini (M1). The connection drops irregularly throughout the day. I've done lots of various tests and can share all of the following data points:
* Not related to idle (it happens sometimes when I am actively typing)
* Machine-specific. It does not happen on my M2 MacBook Air. Only on the Mac Mini.
* But not user account specific on the Mac (I tried with the Guest account on my Mac mini and had the same problem)
* I tried reinstalling the FortiClient software, problem persisted
* Mac OS Ventura is completely up to date
* Does not appear to be related to any other recurring process on the Mac (e.g. Time Machine)
* I did not have this problem with my previous Mac and do not have it with my MacBook Air so again it is a machine-specific problem and not my work VPN account or login, etc.
Any suggestions? Thank you.