VPN Events - "A certificate is updated" every 10 seconds

[WWT]

I'm the new systems administrator for a pair of HA Fortigate 200D.

We've been having some recurring VPN issues which were in place before my starting at the company, and in the course of troubleshooting I've been baffled by these "A certificate is updated" messages in the VPN Events log.   They're showing up every 10 seconds.

After doing some research on my own I discovered that I could use 'config vpn certificate crl', edit the correct CRL and then 'set update-interval'.   I did this, setting it to 86400 seconds (24 hours) but am still getting these messages every 10 seconds.

While I can filter them out of the logs to do my troubleshooting, I'd rather get these reduced to a sensible frequency.    Are there any further steps I can take?