[4.21] 13.12.2014 Kalista Rend (damage bug)

[GAMEPLAY] How do you find that bug:

1. Play kalista
2. Buy some ad items and rank up related ability to max level
3. hit any target with 5-6 or more spears and consume ability
4. look at damage dealt then read ability tooltip. To compare that damage.
5. now sell ad items and stack same amount of spears again.
6. look at damage and it should be almost same, because additional spears not scaling off attack damage.

So the damage is notably low, because it seems like additional spears not adding bonus damage what scales of ad, and the only base 31 damage is stacking making this ability really unworthy.