As the topic says, my trappers do not use their backpacks when gathering fur and meat and bringing those back to my settlement
Have you inspected their backpack to see if they put at least one item in it?
I can confirm this, I’ve seen the trapper leaving his items on the ground, and bringing them one by one to the stockpile, but I think that I’ve also seen him using his backpack properly sometimes.
I have watched one of my trappers for a couple of minutes. Her Backpack was empty all the time.