Hey!
I tested this in Explore.
Ironhawk Artillery Support triggers first, doing damage to all opponents as expected. Then Orc Armor triggers. Which replaces the armor lost.
If the Orc Troop was at full armor, it appears to cancel out because it is reduced then instantly restored to full. However, both traits do trigger.
Also tested on an enemy troop with the Orc Armor trait, that had no armor. The damage is dealt to health as intended, following this Orc Armor triggers giving 5 armor.
Both these mechanics and interactions are working as they are intended to. Based on the test myself & another team member went through.
Jeto - Support Team 