Cripes, that's insane. I didn't know arrows could have bonuses. :P
I found a quiver of poison arrows once with an insane list of bonuses. When I picked them up, though, they merged with the other 300 poison arrows already in my inventory and lost their special attributes. I think this might happen if you have very high luck (as my hero, usually the lead character, does). You get to find more items with high attributes, but I think the game (mistakenly?) applies this to quivers of arrows as well.
