Well, making a fire is a one-time task rather than a "career option" that you can set in a villager's skills preference on the details screen. It's more like bringing a collectible in (the grass, the wood) than building, researching, farming or parenting. And bringing collectibles is easily interrupted by switching tribes or quitting the game.
Yup thats what i was saying, answering the question posted
Are there any other things that for sure the villagers will not continue with when you leave the village?
I know these tasks are one time tasks, that will be interuppted.