This isn't a bug, but a few times I've used the Check Game Variables Step and wondered why it didn't work. Then I remembered it was because the Is Valid checkbox wasn't checked. That means the Step does the opposite of what it is supposed to do.
It seems to me this should be checked by default when creating a new Variable Condition. Or better yet change it to Is Not Valid, to represent the rare need of reversing the function of the Step.
Anyone else agree or am I just nitpicking?