PlayStation 4, first version.
Official pve EU.
Siptah 8006.
The thralls that equip the coup de grace, are killing easily the veteran mini bosses that shouldn’t be hurt with truncheon because you cannot tame these npcs! If an npc is lvl 1 cannot die from coup de grace (or die very slow) but surely not getting knocked down (which is correct, because this truncheon knocks down only named npcs).
I wish you’ll never fix this bug because surges are really easy now (sorry for the joke, but it’s so cool to make a surge so easy 
).
Still, it’s a bug and must be reported handy or not. Have a nice day!
Edit. Only the Aquilonian surge veteran npcs (1 skull) don’t die from coup de grace, which is correct, all the rest (darfari, aesir, etc…) die!