I have 3 emails configured

OK, I had 2 types of members in the Target list: 1. our own system users, 2. a couple contacts with gmail addresses ( 1 valid & 1 invalid for the bounce test). So when I deleted the 2 gmail accounts from the outbound mail queue, it sent out emails to all 4 system users. Then when I updated target list to remove system users & leave the two gmail contacts - it would hang in the queue - I even deleted the bad gmail email and the one remaining valid gmail contact still stayed in the queue (yes I did the mass update to remove the in process flag prior to sending again).

I did another test to add a contact instead of a system user to a non-gmail email account and that went out just fine - so Sugar or Google is preventing sending emails to gmail domain contacts.