Mail9.2: "External (TLS client Certificate)" versus "password"

Hello,

So I have several Google Mail accounts running under Mail 9.2 in El Capitan 10.11.3.

It is weird that some Gmail accounts show under the "Advanced" tab "External (TLS client Certificate)" as authentication, in combination with an SMTP server authentication of "None". The other Gmail accounts show "Password" in both settings.

There does not seem to be a any method to this. Some of the accounts have 2way authentication switched on, some do not, and it does not seem that there is a connection to the External vs Password settings.

This is disconcerting. Why the difference? Is there a difference in how secure each method is?

All accounts are similarly set to use SSL on the same ports and do not allow insecure connections. I could try to delete and add accounts to see what happens, but I thought I first ask if anybody knows what is going on.

I suspect that "None" in the SMTP server settings is ok if connections run via OAuth / certificates, but it still is a misnomer to display none. I can send & receive mails fine, so all this does not influence functionality currently. Just weird, as in OS 10.10 all accounts used "password" as setting.

Thanks.