Twentyseventeen background bounce

I have have been using the twentyseventeen theme for my blog. I started off by having posts on my homepage but I have recently changed to having a static page and since the change when scrolling on the home page the background image bounces it zooms out the back in again I have tried it on all browsers and it is worse on chrome and Firefox but is minimal but still noticable on safari. When I disable the background image the scrolling is fine I have searched the internet with no results and also these forums I would appreciate any advice to resolve this issue.

• This topic was modified 2 years, 9 months ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not an Everything else WordPress topic

The page I need help with: [log in to see the link]