I tried to search for other issues about this but surprisingly no reports seem to have been made.
When trying to access the Monsters List linked from the 5e compendiums page, the spinner on the page just keeps spinning forever and nothing loads.
It seems that you are accidentally encoding some JSON through HTML-entities, since looking at the browser console, it looks like
var listdata = {"name":"3Monsters","category&q...
is the offending line on the page code.
This happens on both latest Firefox and latest Chrome.
Hope you fix it soon and I can get back to planning my campaign.
