Hey Steve! Thanks for the reply. I've discovered more things that will be helpful. The users that were getting the emails were owners or list moderators of the list. The graduates list has ~2500 list members and 4 owners, which is why that one says 4 recipients. We changed nothing before it stopped working, but I discovered about an hour ago that if we change the 'default-owner-pipeline' to 'default-mailing-pipeline' in the list setting then all members start receiving the emails. This leads me to believe that there is some sort of corruption or erroneous behavior with that particular pipeline and I do not know why. now, to answer your questions: How many people are on each of the lists which exhibit this problem? we have 5 lists, 4 with ~2500 members and one with 16. all lists have the same pipeline issue. Have you checked for unsubscriptions or disabled subscriptions? Yes. All members are properly subscribed and there are no requests to approve. Are you sure all subscribed addresses have been validated by the subscribers? We don't check for that. All members get the emails if they are in the list, and we have a script that adds members and subscribes them that works well. How do you know only 3 recipients are getting the emails? because, for the test email list, the logs and the recipients showed that only 3 of the people on the list (who turned out to be the owners and/or moderators) were getting the emails. Is it the same person every time? no Is it the poster themself? no Is it a person who is also an explicit addressee yes Are they on multiple lists and only receiving one copy? no and no. if it works, they get every email we are using Microsoft exchange services, so the google thing isnt an issue.