I don't think that this is a bug anymore, as the issue still exists. (I think it's intentional, maybe to save up some space). When joining a new game, the variable will be set to whatever it was when it was last saved. While this means you can no longer have a highscore counter, it also creates issues for online games as well. For these, make sure that when new players join, they wait the maximum amount of time between cloud var updates so that they don't override them with their “reseted” variables.