[GAMEPLAY] Kayle passive working backwards

Alright so I played a game with Kayle, I was using the Viridian Kayle skin and was up against a Vel'Koz. I noticed partly through the game that every auto I did was doing less damage. I thought this was very interesting as Kayle's passive should work such that each auto does more damage because of her built in armor shred. I tested on both minions and summoners during the game both of these resulted in the same thing less damage every auto attack. I was building AD Kayle mid don't know if that matters, but I thought I would include all of the details.