Piston pushing redstone block bug

When a sticky piston pushes a redstone block veritcally and the power source to the piston is removed, the piston stays extended

I expected it to retract when the power source was removed

The piston stayed extended until the redstone block was removed (removing the blocks around the piston didn't do anything so it isn't a block update issue)

Steps to Reproduce:
1.Place a sticky piston with a restone block on its surface vertically
2.Put a torch under the piston
3.Remove the torch