I agree it's a bug, there is a another more glaring bug really. Why can one dual wield hand crossbows? With no free hand, how could one load the thing? And the most important question, why would anyone use any other ranged weapon in the game, given they're are implemented in this way? Presently, they out-class all ranged weapons due to this. At times, I fear Larian is just not thinking things through.