I just wanted to confirm that facebookcorewwwi is working and is under active development; we are currently working on scaling bandwidth so that we can support more people who want to use Facebook over Tor.
The facebookcorewwwi URLs use (and need) subdomains which are respected by web browsers, albeit that they are invisible to the Tor protocol.
The URLs are as follows:
https://www.facebookcorewwwi.onion/
https://m.facebookcorewwwi.onion/
...the latter URL ("M-site") is a web-version of Facebook designed for mobile devices, which uses Javascript and yet can *also* be used without Javascript being available at all.
When an issue (potential bug?) is raised with us, we generally attempt to reproduce it. Our rule-of-thumb is to try reproducing the issue on a recent (ideally latest) version of TorBrowser, without extra extensions, and with the TBB "Security Level" set between Low/Medium-High (for www) or between Low/High (for m-site).
So far I have only managed to reproduce the "looping" issue once, and then only by exceeding the bounds of our "rule of thumb"; I currently suspect that this behaviour is related to manual configuration of Javascript controls in such a way that JS is only partially-enabled for the site, leading to anomalous script behaviour.
Where Javascript is considered a risk it seems wisest to disable it entirely (Security Level: High) and then use M-site; restarting Tor Browser should clear any active state that would trigger the issue.