Villagers tend to wander around a lot and after they get too far from their work stations, they forget their professions. You click the villager and it's trading screen just flashes all over again. I've pushed them back to their stations (sometimes moved with a boat because they wander TOO far away) and that seems to fix it, they suddenly remember everything... until it happens again.

They also seem to forget to seek for a bed in this weird amnesia state.

Then while a villager is in this amnesia state, another villager with no profession can 'hijack' their work station and I have to create a new one for them.

I should probably make another thread but I've also observed other bugs in the villagers:

• their professions do not reset if you remove a work station (1 villager, 1 station)
• they sometimes jump out of their beds at night and start seeking a new bed even there's one right next to them
• villagers can't seem to properly understand how to enter "round" buildings or anything with fence as decoration, etc., only the basic shapes (they just stand next to the door)