So what usually happens is when you drag the tool around the rails get tweaked one way or another usually worse when you start in a corner. I am sorry I need to do a little guide for this but the answer is usually pretty easy. To try and describe what is happening if you have the tool all the way on the left side and pull it towards you, the right side will follow behind and give you crooked cuts.
Get the tool where you want to start then measure all 4 rollers and set each side equal (x and x, y and y). I measure from the corner block to the roller and check and set each side, and I usually double check.
Let me know if that isn’t clear enough.