This happens to me also, there are no modified inline styles on my site and the full width theme isn’t what I’m after for the front page. (Although it does the same thing anyway)
All the other pages look normal unless they’re set as the “Static front page” in which they do the same as Regina’s site.
Example using my “About us” page:
Static front page set as “About Us”
(No matter which page it is it will look like this if it’s set as the static front)
https://i.imgur.com/wdlpkYC.png
Static front page set as another page
“About us” goes back to normal but other page goes like first example.
https://i.imgur.com/w938xRW.png
