Pistons, Droppers and Dispensers detecting redstone signal 2 blocks above.

If a redstone signal is two blocks above a Piston, Dropper or Dispenser. When a block update occurs on the Piston, Dropper or Dispenser it will activate and remain activated until the signal is removed and another block update occurs.

May affect other redstone devices, these were the only ones I could find.

Screenshots show bug, middle piston is the one experiencing the issue. Right side is expected result.