Issue: Incendiary Arrows on Kipchak Archers are bugged. When you research the Incendiary Arrows upgrade, the Kipchak Archer’s damage decreases by –1, going from 10/9 for castle Kipchak and 12/11 for elite kipchak damage.
Reach Imperial Age with the Golden Horde. Make a Kipchak Archer, check its damage, research the Incendiary Arrows upgrade, and you will see that the Kipchak Archer’s damage decreases.