I set one NPC to remove grass using construction blueprint. When I reenter the bubble, it only finishes removing the grass it was working on when I left. It does not finish removing a number of grass tiles corresponding to the time I was away.
The same happens with NPC set to plant barley seeds into dirt. It only finished one tile when I got back, while it should have finished at least 20 at 1 minute(?) each.
And also the same happens when I set them to deconstruct furniture. They just finish the current furniture they had been working on when I left, leaving the rest intact.