Was just doing a fight on a new game and tried to switch from my bow/arrow to my axe/shield, it changed to the shield, but the axe would not equip and when I unequipped the shield it was lost was stuck with a bow with no arrows trying to punch stuff. I wasn't being attacked directly, there were only 2 enemy's left and they were fighting my troops so the shield didn't get splintered, it just disappeared.
equip was set up;
Bow
Arrows
Pict Axe
Shield