Sticky Pistons Not Pulling Slime Blocks

I used a YouTube video to create what's supposed to be an extending bridge. When activating the "device," all pistons fire as they're supposed to. However, it's observed that the Sticky Piston isn't pulling the slime block. I've attached a link to Google Drive of the allowed 30 second recording the system allows.

Sticky Piston Bug | https://drive.google.com/file/d/14oO9cQocyd4-tPL5MGazgtsDtZXyceam/view?usp=share_link