As I was playing Vayne, custom, Summoner Rift, vs. bots (Just goofing around). I went to solo Dragon, as I used tumble in his lair, my screen and my champion moved to my second tower bottom lane, and I kept attacking the dragon (Though it was shown as me attacking no one.) And I also recived damage, after a couple of clicks and second, I went back to the Dragons Lair. Is this a bug? Does it happen to any-one else? Or is it just a real minor thing? P.S, don't know if it matter's but, I hate the 'Heartseeker' Vayne skin on at the time.

Did you try and test it again, could have been just a glitch?