[ScooterQ]

I've pretty much figured out that the problem I'm seeing has to do with the forum_view cookie not being set, thus causing my unread status to fall back to using lastvisit instead. The forum_view cookie is only set in two places in all of the VB3.5 code and in both cases it's only set if you **are not** using threadmarking.

function_bigthree.php

	if ($vbulletin->options['threadmarking'] AND $userid)
	{
		$db->query_write("
			REPLACE INTO " . TABLE_PREFIX . "forumread
				(forumid, userid, readtime)
			VALUES
				($foruminfo[forumid], $userid, $time)
		");

		if (!$check_parents)
		{
			return;
		}

		// check to see if any parent forums should be marked as read as well
		$parents = array();
		$parents_sql = $db->query_read("
			SELECT forum.forumid
			FROM " . TABLE_PREFIX . "forum AS forum
			LEFT JOIN " . TABLE_PREFIX . "forumread AS forumread ON (forum.forumid = forumread.forumid AND forumread.userid = $userid)
			WHERE forum.forumid IN ($foruminfo[parentlist])
				AND forum.forumid NOT IN ($foruminfo[forumid], -1)
				AND (forum.lastpost = 0 OR
					IF(forumread.readtime IS NULL, " . (TIMENOW - ($vbulletin->options['markinglimit'] * 86400)) . ", forumread.readtime) > forum.lastpost
				)
		");
		while ($parent = $db->fetch_array($parents_sql))
		{
			$parents[] = "($parent[forumid], $userid, $time)";
		}

		if ($parents)
		{
			$db->query_write("
				REPLACE INTO " . TABLE_PREFIX . "forumread
					(forumid, userid, readtime)
				VALUES
					" . implode(', ', $parents)
			);
		}
	}
	else
	{
		set_bbarray_cookie('forum_view', $foruminfo['forumid'], $time);
	}

So it looks like I may just have to modify the getthreads query for this plugin.