At some point I had un-equipped Gnarri's club, and now I am unable to re-equip it.  It says it will break his encumberance threshold.  However, he has no other items, I've not given him anything so he has what he originally arrived with, yet still unable to re-equip his original (and only) club.  In looking at his stats, the maul weighs 25, and he's already at 8/30 so it is true, he cannot equip it.  However, again it's his original club (maul) and he has been given no other items.