I just posted in a thread (in MPSIMS, incidentally), and although the post shows up when I browse the actual thread, no amount of refreshing will make the forum list acknowledge that anything has been added to that thread in the past 40 minutes (not even the post I actually responded to).
I assume something is the matter that will be resolved soon.
Update: Strange… Posting this seems to have solved the problem, because as soon as I did that, and refreshed, all sorts of posts that weren’t acknowledged in any forum view suddenly appeared. It’s still odd enough that I’ll ask what might’ve caused it, though.