When you click into the link from the thread list view of a forum it should take you to the latest newest post. If you want to goto the latest unread you can click the blue icon to the right of the title, this signifies that there are new posts in that thread you have not viewed. Another indication that there are unread posts is the link to the thread itself is bold as well. And last way to get to the first unread post there is a button on the top of the thread thread page and at the bottom that says Go to First Unread, this button only shows up if there are unread messages in that thread since last visiting.

Hope that helps let me know if you any other suggestions maybe on placement or other indicators.

 

Also the other thing you may be experiencing is if you start to scroll before the page is fully loaded the script will not move you to the latest post when you click into the thread.