Statikk Shiv Lighting Bug (not casting)

I noticed in a game I just played as Master Yi that Statikk Shiv would not proc the lighting on the first hit after reaching 100 sometimes (did not pay attention if this occurred 100% of the time). It occurred at times when no abilities were used and no actions other than walking for a period, prior, to the first hit as well so I doubt it is champion specific. Saw it happen at least two times, may have happened much more.