Parallax On Mobile has extra background/grey strip

Site URL: https://roland-richarson-v1.squarespace.com/

Hi,

I'm using index banner function that I enable parallax for the pages - on the site's Artist page

I'm encountering problems with parallax when I view it on my phone

When I'm scrolling, there's this grey strip bit that shows under the banner image, especially when I scroll back up

It doesnt show with the in-build mobile viewer, only on the actual phone screen

and the top banner of a page doesnt have that problem throughout the site.

Is there any code to remove that part? or tweak it?

Thank you