All of a sudden I'm noticing that anything I send out via that account's SMTP server gets sent back to me as well.

It doesn't matter if I send via Apple Mail or right from the GMAIL web UI.

For instance, I send a message to an account at Yahoo and I end up with a copy of it in my inbox for my GMAIL account. WTF?

If I check my SENT MAIL through the GMAIL Web UI, I can see a ton of messages that were sent via Apple Mail and SMTP. WTF is google keeping a copy of mail that I only pass through its SMTP but not web UI? I can't find any settings to modify this behavior at all.

From my Apple mail client, I'm retrieving mail using POP and sending with SMTP. The GMAIL SMTP is my secondary SMTP server, used only when I'm in a couple of mail accounts

I've also noticed that I have about 1000 messages sitting in my GMAIL inbox, but I have my mail client set to delete messages after 1 month - which works fine with my other non-gmail pop accounts.