FortiGate Cluster out-of-sync

Try to edit the second node's IPsec config to match with the first node.

If you're 100% sure the "fg-ipsec-101" is not referred from anywhere (check with "show | grep -f fg-ipsec-101"), reboot the secondary FW02.

This unsync problem happens time to time in our multiple HA clusters (hasn't happened yet after upgrading to 7.2.8 though) and rebooting the secondary regularly solve the problem. I think when the IPsec's config was changed or removed at the primary the secondary's config in the memory goes into a questionable state during sync and can't quite recover itself. It would clear and reestablish in the memory when it's rebooted.

Toshi

The following article is a good one to troubleshoot your issue.

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Correcting-an-out-of-sync-HA-cluster-by-modifying/ta-p/241714

You can download the config from the primary and search for  fg-ipsec-101 to check for references. As recommended, if there are no references for the mismatch try rebooting the firewalls