Cassiopeia Ult Misfire/Not Properly Working [GAMEPLAY]

Two things, occasionally (about once per game) Cassiopeia's ult goes off in the wrong direction, and something (though less frequent), the ult fails to take effect despite clearly hitting it's mark which is clearly facing it, this usually (but not always) happens when being dashed toward, most notably in my memory is when Gnar jumped toward me, the ult took no effect.