Seems like all Titan AoE grenades don't actually proc the Armaments armor mods. EDIT: I am using them correctly (Taken against Taken and Fallen against Fallen). I have used all of the Titan grenades and the only one that consistently seems to work (100% efficiency) is the Fusion Grenade while using Ashen Wake gauntlets. EDIT 2: As far as I have checked, all of the Warlock grenades, AoE or not will proc the Armament mods.