[Robotic Pope]

This does seem to be a connectivity problem then. On xbox if you have any problem connecting to another player you will be unable to join the game which is why nobody on xbox has had this happen. This is probably different on Playstation network, where you can join a game while only having partial connection to the host. This will cause the hosts game to become confused.

As I said, lag alone can't cause wrong spawn points and invisible people in the lobby before the game. This is complete lack of certain needed information because the users router is most probably blocking the ports their PS3 needs open to comunicate properly. It might help to check your NAT status too.