I think my question is the same as yours. I set up a phone for both myself and my wife. Even though we both have our own cloud accounts that each phone are tied to when my wife makes changes in the calendar the invitations indicate that I made them. Where are these usernames coming from? I've checked her phone and it's set up to be hers with her name...etc but still indicate that I've made them when done from her iPhone. Did you get any responses to your question?