<GAMEPLAY> bug on Viktor

I was playing a normal draft game with my friends when I encountered this bug: it is basically Viktor's q not running out when attacking structures. I didn't notice this untill the end of the game where we were pushing down the inhibitors and nexus towers, but I was able to constantly deal the extra magic auto-attack damage to the turrets, inhibitors, and the nexus.... basically 3-shoting the inhibs.

I am not sure if this is how it is supposed to be (the more AP you have, you are supposed to deal more damage to structures) and I just simply mistook in the bonus damage I have from the AP for the Q magic damage triggering, but I found the constant added damage too much to think it so, and am reporting this bug now.

The Link is the game where I noticed this happening.

P.S. It is my first time trying to report a bug and I hope I wasn't making a fool of myself