Redstone block and piston glitch

When a piston (sticky or normal) pushes one of the new redstone blocks the current from the redstone block stops the piston from retracting.

What I expected to happen was...
when I turned the power off the piston would retract.

What actually happened was...
when I turned the power off the piston stayed extended because of the current from the redstone block.

Steps to Reproduce:
1. Place a piston.
2. Place a redstone block in front of the piston arm.
3. Power the piston so the arm extends, pushing the redstone block
4.Turn off the power source for the piston.