Minecraft up-facing piston/sticky piston pushing redstone block stays on

I expected the sticky piston/piston to pull the redstone block back/retract it's arm when power from the leaver ceased.Although the block did not move.

How to reproduce:
1) Place a sticky piston/piston facing the sky.
2) Place a redstone block ontop of the sticky piston/piston.
3) Power the piston.
4) Remove the powersource from step 3.

Additional notes:
Valid power sources (the ones that I tried, atleast):

• On-state redstone dust

• Redstone torch

• Wooden pressure plate w/item on it

• Stepped on wooden pressure plate

• Stone pressure plate

• Iron pressure plate

• Gold pressure plate

• Wooden button pressed by player

• Wooden button shot by arrow

• Stone button

• Redstone block

I also provided a screenshot.