Sunder Bug, Warrior/Mace Skill.

Dont know if its supposed to be like this but when I put the support gem splinter on the Spell Sunder it wont shred armour. Is this an issue with the fact that sunder consumes fully broken armour? I am playing a Aftershock build and I want sunder to shred the armour itself on repeated waves. At this point there is no indicator that any armour gets shreded and I dont get the bonuses from scavenged plating.