Pistons pass falling blocks

Steps to Reproduce:

1. Create world any.
2. Place two pistons (above the sticky piston put the usual)
3. Connect to sticky piston repeator (Volume 2)
4. Above repetor set any block
5. Put readstone dust on setted block
6. Сonnect the entire circuit
7. Set on basic piston 2 falling blocks (For example: "Sand")
8. Power the circuit from the button
9. Wait
10. Power the circuit from the button