similar characteristic to yours. chrome based browsers work, safari keeps loading web page forever.
i think that it have something to do with akamai services (they are used by facebook and other companies to spread the load on webpages to different servers). i have same problems with pages served by akamai which need few reloads to show properly. as far as i know apple is using their services too.
by loading facebook different browsers and looking into development console i get this:
- chrome: no problem, logs seems ok
- safari: no log at all, stops loading before any log can be seen
- firefox: stucked when accesing data from akamai. sometimes, after few seconds it loads the data, subsequent reloads work, because the data is caches localy
btw. tested everything previously mentioned and also lot of stuff not mentioned. i was already using google dns, but in the process i've tested different dns providers without any success.