Hi, Did you ever get this issue solved?  I am having the same issue.  My Seller Hub page runs vertically all the way down the page like this.  It does not matter what browser I am using, whether it is Chrome or Microsoft Edge.  Sometimes I can get it to display correctly by repeatedly hitting the refresh button, but as soon as I leave the page and then try to go back, it is right back to the same thing.  i have tried everything and nothing works.  It is very annoying and was wondering if you found out what is causing it.  I have tried the Hard Refresh, checking extensions on my PC, enabling virus protection temporarily, clearing cache and cookies, and noting works to fix it.