object vpn certificate local cannot synchronize

Hello,

The problem concerns the vpn.certificate.local object on devices in the HA A-P cluster based on FortiOS 7.2.10. The object is not synchronized in the cluster, which causes out of sync.

What was done?

1. Manual recalculation and re-execution of synchronization on both devices does not bring results.

2. Restarting the devices on both sides does not bring results.

3. Disconnecting the cluster, hard resetting the secondary device, editing the configuration downloaded from the primary device and uploading the configuration to the secondary device so that the configurations are identical 1:1 and reconnecting the cluster, also does not bring results

4. Using the technical tip from the link below was done and also does not bring results:

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-HA-out-of-sync-issue-due-to-vpn-certificate/ta-p/192198 

All of the above methods help only for 3 minutes, then the same object stops being synchronized again, updating to FortiOS 7.4.5 gives the same effect, i.e. the problem returns.

Any logical explanation for this?

Best regards,

Adrian