The trollhammer torpedo ranged weapon introduced in the lastest DLC is currently not working as intended and worse with the engineer class:
It’s weapon characteristics classifies it with piercing bolts = 1 shot can hit 2 enemies not working.
As soon as it hits something, it explodes.
The engineer talent Armor Piercing Slugs states: “non-explosive shots ranged attack pierce 1 additional enemy” not working.
The trollhammer torpedo is clearly an explosive, both lore-wise and game mechanic (it has AoE), but it benefits from the talent.
So right now engineer is capable of fixing the trollhammer torpedo weapon characteristic bug by utilizing the talent bug.
The trollhammer should as standard pierce 1 target, and the talent shouldn’t add a 2. pierce.