Here's another example of how bipolar Riot is with balancing.
Past Black Cleaver changes, for those that miss it.
V3.9 Can no longer apply more than one stack of Armor Shred in a single basic attack.
Then later
V6.16 BUG FIX: Fixed a bug where an enemy hit with multiple shells from Graves' basic attacks only applied a single stack of The Black Cleaver.
Notice how they call it a bug, when its clearly been intended in the code.