When one receives Topic Reply Notification emails there is a link to go to the last unread post.

Example: https://area51.phpbb.com/phpBB/viewtopic.php?f=75&t=44051&view=unread#unread

If the user is not logged in there are two things that normally happen (in 3.0.x):
1. The user is asked to log in.
2. The user is taken to the last unread post after logging in.

Right now neither is happening. The user is instead taken to the topic's first post.