I got the same 502 bad gateway error on Friday when I clicked the link out of habit.
Clicked it again yesterday, again out of habit and it went to the site.
I did not specifically save any of the pages or tell my browser to cache or save the pages.
Just now I cleared all of my browser cache, cookies, history and all other forms of stored data I can find.
Link still goes directly to the site and the 20 or so pages I checked including sections of the site I have never been to all work fine.
Got an explanation?