Villagers of the wrong profession are farming, even if there is a farmer in the village.

i lately saw villagers like blacksmiths or clerics or butchers farming. to reproduce, load the seed 10 on default superflat, then type in the command tp 777 5 -12751 look at the farm behind you, then a blacksmith and a butcher will farm in front of your face. this might actually be intended but i honestly dont know. the villagers must be stealing farmer AI.