Pistons can detect air blocks in push limit without filling them

I Love Ghost blocks glitch. but this is not about it.
The piston cant push in push limit. It's good.
But It's bad when glitches Happen.
I made a small but fast Redstone device. It's pretty Awesome! but glitchy.
I made a video for it. The link is:Video(It was too big that I couldn't upload it as an attachment. Chrome and ie: right click> download link, Firefox, and edge: click ) Thanks, Microsoft!!
#ILoveMinecraft
#IDoMinecraft
Best regards,
Jamie.