george, I think that is a setting in VB. I know it is in InvisionBoard forums. Admins can set it so that, for example, a reply made within 15 minutes will get merged with your previous post in that thread. Maybe that is set incorrectly here?? I don't like that setting no matter what the time limit is. All new replies should show up as individual replies in my opinion.
Of course, I am only assuming that is the case here. It could be a glitch or something.