Safari 11.0.1 reformats many websites into something like a .pdf doc and eliminates most interactive buttons!
I've got a Macbook Pro Retina Display running Sierra 10.12.6. About half the sites I visit with Safari are fine, but the other half reformat into a rather non-Internet looking document, almost like a .pdf document. Links to related websites seem to work, but the buttons allowing you to maneuver within the website are missing. Chrome, however, works fine on all sites.
MacBook Pro with Retina display, macOS Sierra (10.12.6)