I tried to get some wins the other day for the HOF achievement with 3 friends. We decided to just quit out each time and take turns 5 wins at a time. I went first and got my 5 and then after that no one could register any more wins on the leaderboards including me no matter who hosted. We couldn't figure out what happened and just decided not to do it. I am not sure if the last update fairly recently changed something with this or not.
Perhaps there was lag with the wins and they showed up later. I will check this and update if so.