[Gameplay] Mordekaiser W won't go on target allies.

I was playing an aram as Mordekaiser and I leveled up my q , w, e first like normal then get to turrent and teamfight breaks out. I try to cast my w on my tank and it goes to the backline annie. So I thought it was just the tank being out of range. Later on everyone was a little spread out more and our tank and miss fortune were near me both were in my range. I tried to W the tank again and it went onto miss fortune. Which then got me and the tank killed. I don't have a video of this happening but I can get one later on.