While looking at any of the normal main pages (“Latest”, “New”, “Unread”, “Top”, but not “Categories”), with “all categories” and “all tags” selected (doesn’t seem to fail if any particular category or tag is selected), clicking on the same page link in the top bar gives an endless-spinning loading indicator. Going to any other page link is OK. The same applies for keyboard shortcuts.
This behavior seemed to start after the recent Discourse maintenance activity.
(Safari-equivalent on Mac OS X.)