Hi Rick,
I "was" confused.
At my new forum (v6.4.2) located at
forum.RiverfolkFestival.org , I have a category "General Discussion" with a forum "News, Updates & General Information."
It appeared that when a visitor/user clicks on "News, Updates & General Information" they only see the first thread/topic unless they click on Index.
The problem was a new user created a new thread as a reply to a previous post. Sorry for the trouble and the slow learning curve.
Thanks