Does this still happen? I can't reproduce, not even with ancient Firefox version:
https://i.imgur.com/Cftmi6D.png
Also I haven't encountered any connection issues or "downtimes" lately, even though I visit the forum on a daily basis.
(BTW: If Firefox reports "Content Encoding Error", it is very well possible that is a symptom of the server being "too busy" and thus sending incomplete/corrupted data)