I do much the same thing in the early part of the game -- as long as the villager has at least trainee level in farmer, they'll harvest honey or pick fruit occasionally (and more often if the food stores are low) - even though they are assigned to other jobs. It works for me until the population gets above 15 or so; after that, I have to start assigning villagers to farm.

They won't do this if they don't have any farming skill, so you have to train them a bit (I go all the way to trainee to be safe, but that may not be necessary). It's a great way to maximize your number of researchers early in the game.

I think this was a tweak from the behavior of peeps in VV2, who would endlessly worry about an empty food bin while the crops sat unpicked in the field.