Step 1: Open up lots (20+) of tabs to comments pages.
   Step 2: Close browser (with setting to reopen tabs)
   Step 3: Open browser

Not complaining, if anything it will help me actually read some of these :) Just saying if you ever see an error from HN that has a bunch of "NO_CONTENT" pages, you might have opened a few too many tabs...

Edit: To get unblocked, change your IP.