Cover page bug

Site URL: https://gregorylassale.com/

Upon loading, my cover page headline, body, buttons and social icons are offset for a split second, then jump to their normal location. For some reason, the branding isn't affected. 

Squarespace couldn't help when I approached them about this a little while ago. I'm really hoping someone here will be able to assist. I use the Sofia template (Brine family).

Thank you.

I think it took a while for all css and assets to load, that make it jump

I duplicated the site and the problem persists after removing all custom CSS, local and site wide code as well as all blocks. I also tried loading removing all cover media, but nothing changes. Sometimes but rarely, the bug doesn't occur, seemingly when I load up the cover page after being off the site awhile. When I refresh the cover page or load it from within the site (by clicking the branding logo), the problem seems to happen every time. I'm including a link to a screen recording so you can visualize the problem.

https://www.dropbox.com/s/t9v5wnjnt9z7mv1/CleanShot 2021-04-07 at 16.24.24.mp4?dl=0