I have always had issues with Gmail notifications as well. Not quite the same as yours but possibly related. My problem is that I want my notifications to be silent and no vibe which they have been since I started using Android. No problem there. The problem is that I would like for starred conversations to trigger my notification tone & vibration... just like my text messages, IM's and other more urgent type messages. I have yet to be able to get this to work properly and I wonder if it has something to do with your issue. I get LOTS of emails and maybe it's not a bug elsewhere but maybe it's that I get so many emails it's the 3 email issue you're experiencing.