You appear to be correct. I just recently updated the forum software so I imagine something broke with this latest update. I'll see if I can figure out what exactly is causing it.
Edit: Definitely something they broke (along with the display of locked forums and forums not being properly marked as read when reading the last thread in them). I thought maybe it was a template change that I didn't account for but even using the completely unmodified default theme, that error is present.
Edit: Definitely something they broke (along with the display of locked forums and forums not being properly marked as read when reading the last thread in them). I thought maybe it was a template change that I didn't account for but even using the completely unmodified default theme, that error is present.