I think this should work:
	// Is this a moved topic that we are redirecting to?
	if (!empty($topicinfo['id_redirect_topic']))
	{
		markTopicsRead(array($user_info['id'], $topic, $topicinfo['id_last_msg']), $topicinfo['new_from'] !== 0);
		redirectexit('topic=' . $topicinfo['id_redirect_topic'] . '.0');
	}
in Display.php about line 133