There was a glitch when shipping "By Hand" and transferring multiple puzzles at once.
This glitch may have caused issues with other forms of shipping besides "By Hand" when closing out a transaction that included multiple puzzles. The glitch was that only the first puzzle was properly updated and the others may have gotten left behind or not had the shipping details properly attached. I suspect no one noticed the issue since it was not reported by any users. But it was discovered when we tried to do a hand transfer ourselves with multiple puzzles going to one person in a batch.
This issue has been fixed.