I added the "Centennial Group" as an owner, but that didn't change the behavior at all. This is the "out of the box" set-up of the Intranet Portal workgroups.
When I click on "Manage This Workgroup" and then click on the "Forums" tab, I am presented with this:
However, when I click on the pencil icon to view the topics within the forum, nothing shows up. (Second picture in original post). I can CREATE forum topics here, and they show up in the correct spot in the workgroup, but they do not appear in the management screen.