The stone statues outside the church are 100% resistant to piercing because they're made of stone. Somehow the cultists inherited their settings. So this was a bug, fixed now.
not on topic but related:
doing the stone statues outside the church get's you ...
- fighting nearly 10k XP and some loot, but
- doing the right conversation option zero XP and no loot
kind of inbalanced due to missing a good junk of XP while not fighting
