This feature is incredibly annoying.
Please let us disable this.
I gave those characters the items explicitly because I *want* them to have them. This just serves to add a ton of tedious micro management without actually doing anything useful to me.
I'm essentially being treated like a sentient garbage can where everyone throws things into, leaving me constantly encumbered and undoing all my inventory management every single time I change companions.
As an extra bonus once I transfer the items back to the party member, their inventory will no longer rearrange according to the selected inventory arrangement option. None of the options work at all.

I'm not sure what the benefit of this is, but at the very least make it optional, it pushes into the game breaking side of sheer aggravation.