Unable to recreate an effect on other pages

On my “arya” page, the landing page image stays fixed and fades out as you scroll down.

On every other project page, the landing page image doesn’t stay fixed despite the classes being exactly the same.

What is causing this effect to work on the “arya” page, but not on any other page?

Any explanation or alternate approaches would be appreciated as I’m sure there’s better ways to accomplish this effect.

Here is my public share link: LINK
(how to access public share link)