I wrote a short script which fixes the problem. Simply execute it before
connecting to the VPN.
https://gist.github.com/SydoxX/f40a9d4d7af414049b6e07092e8bbc2b#file-forti-fix-sh
Same issue on Fedora 38. There seems to be a problem with the device
being set to unmanaged when it needs to be up to be configured. device
(vpn00b09c95fd): state change: activated -> unmanaged (reason
'connection-assumed', sys-iface-state: 'managed'...
