It seems there is some odd stuff going on that I've finally noticed to be limited in scope. When I read new posts, they are usually given the red underline, as they should. However, when new posts are made by one certain user, namely Dr. Bunsen, they don't get the underline. Everyone else I seem see the underlining, but his posts alone show up with a "new" tag in the tracker, but fail to get red treatment in the actual thread.
Click image for the original link.
The problem isn't a lack of an underline, it's a lack of a title to have that underline... weird... Looking at the source, the markup is there, the title is just empty. It could be that he's putting something in there that drupal is parsing-out, it could be that the script to generate an automatic title isn't working with him... there are a bunch of possibilities.