A filesystem on the TM/METAL server filled, and I had to take web service offline for several minutes while I cleaned things up. I think it's possible some forum posts failed while the filesystem was full, so if you posted later in the day and in the evening of May 7, check to see if your post is there.
The underlying problem seems to be an even more intense barrage of web scrapers trying to load pages from TM. I probably need to do a lot more to block these requests without disrupting legitmate users. I think it's gotten to the point where these things are hitting the database hard enough that the performance of the site is suffering.