[Gameplay] Nami W does not heal for correct amount on Howling Abyss

In Aram I was playing full AP Nami and I noticed that my w was not healing allies like it should. The W was rank 5 and should have been doing 185 + ap heal to allies, but instead it seemed to be randomly doing anywhere from 60 to 160. Some heals did increase because of my athene's, but it definitely was not what it should have been. It worked correctly when I self healed, but on allies it didn't. Even if I bounced it off an enemy, the returning heal was less than it should be. I have only noticed this issue on Howling Abyss.