The problem appears to be fixed. As I had hoped, once we caught up to the future and into the present again, the posts started bringing the threads up to the top again.

Now my only problem is that all mine show in Central time instead of Eastern time. Is that just me, or is everybody not showing the posts in their local times? I don't know how it worked before the upgrade, but I assumed everybody was seeing all the posts with their local times, wherever they were in the world.