A village has one brewing stand. The cleric that works there is master level. New villager is born and grows up, then becomes a cleric, stealing the original one's spot. The master level cleric doesn't do work anymore, he wanders around, and I cannot trade with him because the trade window disappears immediately after being opened. I can see it for maybe one frame.
This has happened to me multiple times with multiple professions.
Not sure what causes this or how to replicate it, maybe if the first villager wanders too far so the second one thinks the job is available.