When expecting a villager to take a profession from the brewing stand (cleric) the villager cannot access the stand unless it is on the ground level. Villagers cannot "reach" the brewing stand if it is on a "table" or "bench".
Place brewing stand on top of a block.
Spawn villager. Notice he does not accept the cleric job
Move the brewing stand to the ground/floor
Villager immediately accepts the job
I think it is related to or caused by this bug MC-156126