I blame gremlins.
I'm only half-joking.
Long story short: Something that should only have happened when done by a person somehow (apparently) got done by our computers. And left at least three people in my office going Huh? (Number of "Huh?"-ers to increase when we're back at work tomorrow trying to figure this out, and hoping it's not some huge program problem.)
I wonder sometimes if machines have moods and we just don't realize it yet...