Notifications for discussion replies posted via email not being sent with auto triggered cronjob

At first I thought this was an issue with just my installation but I have now confirmed this same behavior on a fresh, bare-bones installation on my server and 2nd bare-bones installation on Pantheon.

I have set up OA as described in Mike Potter's blog post here:
http://www.phase2technology.com/blog/using-email-with-open-atrium-2/
When an authorized user replies to a discussion post notification via email, with a properly formatted subject line (including node id and the security key) and I run cron manually by clicking on "Run Cron" (cron configuration page), MailHandler retrieves the email, Feeds Importer posts the reply AND notifications are sent to the same users as the parent node. The same thing happen if I click on the "To run cron from outside the site" link with the cron key in the browser where I am logged in as the site admin.

However, if I let cron run as schedules (every hour), or triggered by a cronjob setup w/ crontab, or by loading the "To run cron from outside the site" page while not logged in, or by running "drush cron" via ssh, everything is exactly the same EXCEPT no notifications are sent.

This seemed like a permissions issue so I tried giving the role "anonymous" all permissions and still no notifications are sent. There are no error messages generated in the watchdog log that are different when cron is run manually (notifications sent) or automatically (notifications NOT sent).

Again, I have confirmed the same behavior on a test site running on Pantheon.