If you enable automatic renewal the way the guide you linked to shows, it will work.
I saw it working in multiple environments.
However, there is one caveat:
The renewal is only done when the client is connecting to VPN.
Assuming you have configured renewal 60 days before expiry:
Scenario 1:
Cert will expire in 90 days. Client connects. Cert is not renewed.
Client does not use VPN for the next 60 days.
Now cert will expire in 30 days. Clients connects. Cert is renewed during this process.
Client does not use VPN for the next 40 days.
Old cert was expired 10 days ago, but new cert is available on the client. Client connects using the new cert automatically.
Scenario 2:
You have configured renewal 60 days before expiry.
Cert will expire in 90 days. Client connects. Cert is not renewed.
Client does not use VPN for the next 100 days.
Now cert was expired 10 days ago. Client tries to connect and fails because cert is not valid anymore. No renewal possible anymore.
Conclusion: Tune the "renewal in xx days before expiry" option according to your needs.