Mordekaiser W Bug on Howling Abyss[GAMEPLAY]

I played an ARAM earlier today and got Morde. In the game when I went to shield someone with my W, it would always go to the closest ally, instead of the person I targeted it on. The same would occur if I targeted a minion as well. I know that when they changed his abilities, they made it so that just pressing W would target the nearest ally, but in this case, it wouldn't go on the person I targeted in the first place, only the closest allied champ. I tested this out on Summoner's Rift, and this doesn't happen there, only on Howling Abyss.

I also tested this on a solo Howling Abyss game with no other allies, and it would only target the closest minion as well, for example not allowing me to cast on the first minion in a wave if I was behind it. It seems to be related to the map he's being played on I suppose.