I was using a slime block to get out of a secret entrance when I noticed that the slime block launching me out was not launching properly. The piston would still power it to go up and launch you. The real problem was that it would force you over to the side of the block to launch you. To get a better idea of what was happening say you have a piston with a slime block on top. you power the piston to push the slime block launching you, but the block moves you from the middle to one of the edges just before launching you then land right on the edge not the middle where you started without moving the joystick at all.