No problem re: anon posting! Though you can also log in with openID from another site to comment with that account.

And yeah, it doesn't really seem like a bug per se; it's weird UI, but it doesn't let you see or do anything you shouldn't be able to see or do. It's just the whatever-it-is that's redirecting people to that form that's the problem. And also, I suspect, it's conflating those two (?) problems - the original cache problem and the whatever-redirect.