Ah thanks for the explanation! I hadn't considered that you were entering a tile that was already at 0, moving off of it and then undoing back over it. This is because I'm just checking if the grass length is less than it's 'maximum length' and increasing it if it is. I need to implement something that confirms if you have just mown a piece of grass on that turn to resolve this. Thanks for the feedback, I will add that to my list of bug fixes!