Whenever someone puts @Mike in chat it triggers a notification for me (@MikeB).
Any message including @Mike seems to notify him (correct) and me as well (incorrect). From reading this answer wouldn't 'Mike' be considered a perfect match and NOT notify me?
The only time "@marc" will generate a notification for you is when we can't find anyone else who we consider to be a better match, i.e. someone called "Marc" who was in the room during the past seven days, or someone called "Marc Gravell" who was here in the past two days.
I've also received items in my inbox intended for Mike (I'm 95% sure I WAS NOT in the chat room at the time these messages were sent):
What are the solutions in my case since Mike doesn't have a last name on his profile. Am I forced to use another first-name entirely to avoid getting his mail?