Mac Mail Client sending and storing duplicates from Gmail

One of my team members approached me today asking about an issue they're having with their Mac Mail Client and Gmail. I am a Linux user and do not have much experience with Mac, but thought I would reach out to this community on their behalf. - User aggregating 3 email addresses into Mac Mail (Gmail Personal, Gmail Professional, Hotmail) - All email providers set up properly as IMAP (POP on phone) - User experiences duplicates in both Sent folder - User's Drafts folders has incomplete information (some emails are missing) - Mail Server information appears to be correct **Thoughts** I am thinking that this might be an issue with IMAP vs. POP, but I figure that the Sent folder would be suffering from similar issues. What