I pose the question, because, we added small treasures to our coffer initalliy. It was easy since the RHTS were dropping them. We collected 5 of the horns pretty quick, but the inventory only showed 3. It was the same with the Gilded Plates and Harps.
We haven’t bothered to get more than three of the large treasures, because those are a pain to transport.
The coffers are currently broken and not tracking treasures properly, but it isn’t particularly important yet, since the hoard value does not yet serve any purpose. Presumably, the coffers will be fixed by the time it actually matters.