This bug occurs only when the link to comments is opened in a new tab.
Here, using:
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-GB; rv:1.9.0.10) Gecko/2009042315 Firefox/3.0.10
• Safari 4 Public Beta (5528.17), with PithHelmet enabled,
• Mac OS X 10.5.7.