When playing with a friend (who is the host) in a game that is turn-based - classic with 7 computer players (v1.15 and v1.20), often times when it is my turn and my friend is checking out his cities, he will be in the city screen, then I complete my turn. He then gets a message saying that my turn has been completed (while in the city screen), he closes that message, but then can not get out of the city screen. It locks up. He then has to kill the game and we restart it. This should be reproduceble so I hope that you can fix it.