Draven Passive Bug

I just discovered a bug while practising Draven and it's basiacally this:

• When you kill a minion with Spinning Axe you get a timer wich reads: "Draven gets 2 bonus stacks of Adoration if he kills 6 minions in a row without dropping a spinning axe" and every time you kill one it refreshes this buffs timer

• You proceed to get multiple of these buffs until a minion dies near you without you lasthitting it

• Once that minion dies you drop all of these buffs and you have to start over

This is 100% reproducable and I'm not sure if it's intended