XOAUTH2 Gmail Authentication Prompting every sent email

I am sending email through Gmail (not receiving, long story).
The account is too new to use older authentication methods.
XOAUTH2 is my only option.

I believe I have everything configured correctly.

When I send an email, Kmail/Akonadi pops up a web browser and makes me authenticate and go through the 3-page process of allowing Akonadi to send mail.

The mail does send correctly. However, if I send another email (even if I send one immediately) I have to go through the same process. The authentication does not seem to be caching in Akonadi.

Is this a known bug? Is this something I’m only seeing, perhaps because I don’t have a receiving Kmail IMAP account set up?

Please help, this is very annoying!

Thank you,
Matt