Where is this happening? Are you by chance using the beta navigation?

This should now be fixed. Just note that I removed some links and also have recent posts and topics going to the main forums - we'll update these at a later time

It is likely that a server/cache is out of sync -- it'll likely catch up soon

Which links are giving you 404s?

You are right that the cache issue shouldn't span a few days. It'd be a few hours at most

In response to your comments - please copy and paste the link next time you receive a 404

I just pushed out a fix that should not cause that. Let me know if it does

Okay, pushed out another change. Let me know if you still have the issue

Locking as resolved!