Armor pen runes only work on Zed.....

Every champ I have tried armor pen runes the only one it seems to work is Zed. For some reason Vi doesn't even benefit from them at all. Is this a bug or something because every ad champ even Khazix and Kled don't benefit from the runes themselves. The items work but the runes don't seem to do anything. I found this because a zed with just a serrated dirk can burst the crap out of anyone lvl 4-6. Yet any other AD champ with full runes cant burst at all untill they get 2 completed armor pen items. And the runes don't count at all considering they should count as a completed armor pen item.

So you take ad champ that isnt zed give him Ghostblade, Duskblade, and his burst is crazy. If you give that same champ runes+ Duskblade, BF sword his burst is poop even though the lethality is higher.

And somehow Vi doesn't seem to benefit from lethality at all.