NOT Gate / Inverter doesn't effects a piston.

When I was building this Inverter in my creative world the piston wasn't working how he should.

What I expected to happen was...:
When you click the button the the piston gets deactivated and you will fall down.

What actually happened was...:
The piston isn't moving and you see two piston heads for a short time.

Steps to Reproduce:
1. Build the structure showed on the pictures.
2. Press the button.
3. The Piston won't change.