my hearthlings got stuck in this weird loop of dropping items and picking them up. Destroying the stockpile seems to have fixed it.
http://puu.sh/j8j0z/455fa23a66.mp4
For some reasons your vid don’t work for me but I see what you mean and I can confirm this behavior.
this has happened to me too, i even checked their backpacks to see what they were doing.
The way I was able to stop the loop was to either add another inventory area and/or change the settings of the one they are stuck in.
im sure the devs are working on it. 
well this just happened to me too on 2513
had to remove the stockpile to stop them fooling around
seems to be a problem with full stockpiles…
they juggled a fox pelt in and out of this stockpile when pelt wasn’t even allowed in this one
I had a new stockpile nearby just for pelt (as you can see I have lots of them) but they never relocated the pelt from this one… instead they started with this behavior
