http://vboards.stratics.com/uhall/225232-fyi-dont-lock-down-canon-balls-nor-put-them-into-backpacks-vendors.html
Ive been selling cannon ammo sets with everything you need for a pirate fight on my vendor and havnet had a problem with cannonballs disappearing yet. Maybe im either lucky or they fixed it. Then again im not putting them in bags, Im putting them in small boxes