I also noticed that another set of villagers elsewhere still have their jobs and they are under similar underground conditions, minus the bells. They're fletchers.
Removing the lanterns didn't help. I tried giving villagers jobs elsewhere in the same world but rather than take the workstation right next to it when I spawned it in, the villager took another workstation nearly thirty blocks away. There were multiple closer workstations, and the workstation it took had a concrete block on top of it, as did most of the nearby workstations.
I have noticed that this is also happening with witches and witch huts. I updated my creative testing world to the latest snapshot and the witch farm stopped working.
I then created a new world and witch huts wouldn't spawn witches there either. Rather than just spawning witches, it would spawn zombies, skeletons, creepers etc too.
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