Do you have any fixed width content, like an extra wide image, further down the page?
It looks like the container of your Hub site isn't resizing to the mobile viewport correctly and my first guess would be that there's some type of content that can't wrap that is forcing a horizontal scroll and keeping your site at more of a iPad size.
My second guess would be that you might have some custom CSS or HTML that either has a fixed width and can't shrink or is accidentally overriding a mobile breakpoint, but that's hard to know for certain without the URL. Do you have a public URL?
