Kai'Sa W doesn't work as intended upon reaching 100 AP

I keep playing Co-op games with Kaisa to see if Riot has fixed the bug or the W effect not working as intended.

Void Seeker Cost: 55/60/65/70/75 Mana Range: 3000 Kai'Sa shoots a long range missile, marking enemies with her passive.

Living Weapon: Void Seeker is upgraded to apply more passive marks and reduce cooldown on champion hit. Kai'Sa fires a Void blast that grants True Sight on the first enemy hit, deals 20/45/70/95/120 (+60% bonus Attack Damage) (+0) magic damage, and applies 2 stacks of Plasma. Living Weapon - 100 Ability Power (current: 0) - Void Seeker applies 3 stacks of Plasma and refunds 50% cooldown on champion hit.

When I reach 100 Ability power, I don't see an extra stack of plasma, nor is the cooldown reduced when hitting an enemy Champ. What is the point to build AP to get the empowerment ability when it doesn't work? Anyone else notice this? I have sent in the information 2 times to riot through the report a bug tool, but seem to evade them as far as fixing this mechanic.