The companion AI seems a bit off when you have piles of resources apart from each other, the companion will pick up 1 from 1 pile, then walk over to the other pile, and pick 1 up, moving back and forth between the piles.
Occasionally they will pickup a pile, but most of the time they do this, which means you have to stand around waiting for them, or pick it up yourself, and then transfer it too them.
Followers should be smarter of course, but I don't see why they can't mass pickup like us.