So i wasn't playing when the Mage Tower was first built and we got this buff, but the description states for Knowledgeable

When you loot an ITEM which grants Artifact Power in a Raid or Dungeon, there's a chance you will receive a bonus Artifact Power token

Now does this mean killing Bosses has a chance to get an extra AP token? I heard the drop rate was nerfed shortly after its release, but if I go into a dungeon with 5 bosses does that mean I have 5 chances at receiving an extra AP token when looting them?