Apparently I’ve had a batch of comments (I’m not sure how many) be marked as spam and therefore not published. I also found out that a group of comments that I approved somehow got unapproved and two of them ended up in the spam bin (which would have been deleted except that I checked because of the comment eating problem).
If you find that your comment doesn’t show up after a day, please at least e-mail me to let me know. I have no idea yet how widespread this issue is, or if it means I should seek another anti-spam tool besides Spam Karma.
Sorry for the inconvenience!