piston bug

Pistons are glitching, if you power a upside down piston from a block that is on top of the piston then not power it, the piston stays extended.

HOW TO RECREATE
1.place piston upside down (above the ground and able to extend)
2.place a block on top of the piston and place two blocks on any side of the block
3.put redstone on all blocks
4.place a lever on the block farthest from the piston
5.turn on then off
6.piston should be off when the lever is off but stays extended.