I think people have reported a similar bug for the Japanese. But I was just playing a against a Byzantine player who was putting Relics into transport ships (held by 3 monks) and kept loading and unloading them. Eventually he destroyed the ship and significantly more than 3 relics dropped. He had like more than 60 relics at the end of the game. It was really annoying to play against the person.
Please excuse me if this is known, but I wasn’t able to find anything on relic duplication.
I have a replay and a video but I cannot upload attachments.