This is a duplicate of MC-8306, but I found this bug was still present in the game when attempting to design a compact unit for a mob grinder. It was claimed that this bug was resolved because it was a Duplicate of MC-108, which it is not, and is so not resolved. If a piston pushes a Redstone Block upwards, it stays extended when it's power is removed. This should NOT happen because the Piston Arm(the extended part which takes up a block space) is a transparent block, and therefore it should not carry Redstone current.