hmmm, i'm not really sure what you are trying to say, but if you cant equip certain items on certain companions, it might be because their skills are lacking. if when you give them something and they drop everything equipped, then it might be a bug, but i havent seen that one before, but try to look out for what it says when you equip it, it should say something about their skills in certain areas being too low, if its what i think it is

if you put on what shoud they equip for example one handed weapon and shield
they won't look for those they drop evrything they have and go empty handed(sory for bad spelling/wrting never was good at those