I asked the CSM when he came around for the preflight chat. Apparently he said the seat was marked as broken hence the original move, then was fixed so could become occupied again. He did ask if I wanted him to note it on the iPad but I said I was just curious and not wanting to complain. Had a window seat which was the main thing (4K). CC were lovely.

Anyway, apologies for taking the thread a little o/t!