I'm trying to use sticky pistons to block the flow of water, and when I retract or push the piston out, it's about a 50% chance if the game will crash. It's just a simple sticky piston with a lever attached. Three times in a row, right as I flipped the lever to push the block out, it froze. In the photo below, I got lucky and it didn't crash. But then I tried retracting and it froze again. It's a super annoying bug.