Mordekaiser Gameplay bug

I played a game as draven today and apparently whenever i didnt have my spinning axes up my autoattacks would deal no damage to mordekaiser while in his death realm or whatever his ult is called. Im pretty sure i didnt cancel these autoattacks in video thats uploaded aswell but if so then im just pissbad at the game.

1. Draven has to have at least 1 spinning axe
2. Morde has to ult Draven
3. Draven has to drop the axe while in death realm
4. Whenever Draven autoattacks without the axe his autoattack will deal no damage