I have a room in my world with 10 fishermen in chambers of a sort so they have easy access to their barrel and can restock without any hassle. All of which have been traded with so their professions are locked, however, after a while, (specifically when I go to another dimension I think) they with stop working at the barrel right next to them and instead go after a random one which prevents them from restocking until I completely reorganize the whole villager setup for them to find their corresponding barrel again.