Is it possible that it's chats you've already read?
If you've read the chat on your PC, and you switch to your mobile, it will still highlight green, regardless if you've read it or not. (and vice-versa).
Well, I am flying right now, so not sure why the hospital chat, jail chat and a country in which i am not flying to/from is popping up. Once again as i sit here typing this message i know have 3 extra chats popping up, this time South Africa, hospital and the jail chat.
I've seen a similar-ish thing happen a couple times to me today. I was in the hospital, and suddenly a Switzerland chat window appeared. It was entirely blank, and when I said "...hello?" in it, it vanished. I medded out of the hospital and went about my business and 15 minutes or so later, Switzerland popped up again - again it was blank, and again it vanished when I said something in it.