It was also confirmed in the errata for Eote that to use an active weapon quality you had to cause damage.. So no damage no sunder, weapons xould be sundered armor could not also.
In the Item Qualities entry, at the end of the fourth paragraph add: “Weapon qualities can only trigger on a successful attack, unless specified otherwise.”
From sunder
When attacked , the attacker chooses an item open wielded by thd targer (such as a weapn, shield or item on a belt),