Wtf Riot?Why did i get a 15 minute leaver buster for someone else's leave?

I was in the champion select(blind pick)we had a duo jng locked,so someone left,i noticed i was out of the queue,i thought:eh,whatever,i'll just join the queue again.Nope,i got a 15 min leaver buster for no reason!i didn't leave,the only way i could've left was by exiting game,but i was in the game the whole time.I am not even mad about this lol,just wondering if it happened to someone else too.