Redstone block constantly powers piston glitch when it is above the piston

Put the summary of the bug you're having here

What I expected to happen was...:
Once the redstone block was moved away from the piston I expected the piston to no longer be powered.  

What actually happened was...:
Once the redstone block was moved away from the piston it turns off for a split second then turns back on.

Steps to Reproduce:
1. Place a redstone block on a sticky piston, facing straight down
2. place a normal piston underneath with a block gap below it.  (like in the screenshot)
3. activate the redstone piston and then deactivate it.