Mordekaiser Bug
I was just playing a custom match to test out Morde with the new Fervor mastery, also to learn the new jg stuff, etc.
I noticed at one point that I was doing 2 extra Physical Damage to turrets when I had my Q activated. The 2 bonus physical damage would go away after I used all 3 Q hits. I was able to replicate the effect on another tower.