I think you are right. I seem to remember that he dropped the rode with a buoy attached. Not that rare an event; I have even done it. Could be a case of the anchor holding too well (well probably not), likely jammed under a rock. Those can be very hard to get out without a diver at times.
Finished the circumnavigation in early February in Grenada. Have to work on a book project for the next several months so the boat will be waiting for next year.