Hi Ron. The problem simply vanished after the new buyer paid the bank he is borrowing from an additional $200. He made it clear he would eat that cost himself, and not ask me to cover. I never found out what it was all about, but the buyer said he is happy.
That $200 is probably for the bank or some title company to clear up any issue with the title.
Oh, of course. I didn't mean to imply anything sinister.

I'm sure it was a phone call to the previous company, and an electronic signature or two. Half hour of work for an office assistant somewhere.
The new owner's bank wired the money into my credit union account. I gave Joe the keys, logs and J-mo's receipt file, as well as the FAA bill of sale form filled out. The only thing that slightly bugs me about the way yesterday's closing went: I had worked the night before, so I didn't arrive until 3 pm. The buyer, in positive exuberance, had the FBO crew open my hangar and remove J-mo and have it towed to his hangar before I got there. Fine. Then, in a show of good will, he had them drag the canary into my hangar from the ramp where it was tied. However, the brakes were set, the doors were locked and a cover was in place. They towed it with the brakes on. I stopped at the FBO and asked if it was hard to tow, and they said yes, they could tell the brakes were on. Why, then, did they do it? Dunno.
I don't suppose there was much damage, if any. Still.
Anyway, I will have to fly the yellow and white beauty today and make sure it's all good. It's a bit of a relief to be back to owning only one needy airplane. I still haven't named the new one.