It seems to be working now, but most (if not all) of my forum posts from earlier (several hours after the move) never showed up
The only issue that the forum had was the refresh link. The caching system on the site had a small problem deleting cached pages until they expired.
Nothing was really lost, just didn't show up until the cached page expired. The forum's pages are cached for 1 hour. So that's the maximum interval that a post would take to show up.
While it's entirely possible that something got lost, there is no way to find that out. But since you received replies, that means they weren't.