Here's another weird thing. when I restart the app server, it looks like it reprocesses a lot of already processed mail. Very bizarre.
I think I see part of what's happening.
You'll see that the way it determines the messages to read is based on the number of unread, and grabs the last x of those to send off. This isn't accurate though, since I can have (as is the case now) the entire mailbox littered with unread mails.