Well, I don't know what it was, but it appears to be gone. Jessie seems almost back to 100% as measured by how much she kicks up at feeding time. She doesn't kick up excessively but I can entice her to kick up if I make a few playful moves or if she is just feeling "perky".
The swelling in her pasterns is down. I'm still a little concerned with the crack in that hoof. I'll keep an eye on it. The farrier is do out week after next.
It's what I call a fugitive occurrence or, as Paul Harvey might say, "Not why, just what".