Piston contraption moves block sideways and causes piston to turn into an item

I'm taking suggestions for the title.

I made this machine specifically to find piston bugs, found two in one run. It didn't even behave like it did when there was only one block on the side. I seriously don't know how to classify this.

If someone could edit the video to less than 10 MB and attach it here, that would be great.

video