Well, it just happened again, so I agree, it has to be the forum server.
It seems that every time the UU site goes down due to a security issue the folks the run the site add additional security. This latest go around may be causing a handshaking issue with older versions of Safari's otherwise excellent lookup and caching algorithms. And so, yes it may be the UU server's latest settings that are responsible for your Safari stalls.
All that said, The UU server and forum is a great resource for all things and people ukulele given to us for free by volunteers that may be tiring of the job.
Please don't be the the straw that breaks the camel's back.