I have a villager farm that I use to trade glass panes to cartographers for emeralds. All villagers are leveled up to masters. I'll select the glass pane option and the villager emits the "disagree" noise and displays no emeralds in the slot where I normally would click the emerald to trade for it. They are all fully restocked and have access to their proper work stations and beds. I cannot trade with other types of villagers or items in the same way. I have uploaded a screenshot of this as well.