Contrary to websites, mail servers are setup only once. And as ISP start to use deep packet inspection to disable TLS and to prevent man in the middle attacks, it would be great to assign one (or more) certificates to a mail server. Instead of relying on the CA, check the fingerprint and only allow this certificate from now on. Reproducible: Always
Thank you for the bug report. As this report hasn't seen any changes in 5 years or more, we ask if you can please confirm that the issue still persists. If this bug is no longer persisting or relevant please change the status to resolved.