Whitespace at bottom and images jumpy on mobile

Hi Mario, love the Universal Parallax.

But there is an issue on mobile: iOS (iPhone 11 - 13.5.1), Chrome & Safari

When scrolling to the bottom of the demo there is white space and also images jump:
https://marrio-h.github.io/universal-parallax/demo/

Appreciate the work you've done on this.
Aengus