A few problems with the move.

1. If you do it and your target dies as Yi is warming up, he just disappears for several seconds.

2. Not sure if this is intended or not, but if a target is moving away and Yi uses alpha strike on it from max range, he will use the mana and do the animation, but not deal any damage or move towards the target, which greatly decreases its usefullness.

I notivced today as I played with Yi for most of the night. On some occasions Yi will dissapear but the ability will not go on cooldown. I'm not sure how this appears on other peoples screens.

It's not about your target dying. Stuff like Yi being knocked back/up as you use it, your target stealthing or entering brush, all kinds of stuff will bug the skill out and make you disappear for 10 seconds. Plenty of time for them to run or even set up a counter-gank.

I like the idea of Alpha Atrike avoiding damage, it APPEARS to give that intention of moving so fast, you can avoid being hit by anything on an almost molecular level. That's cool. Bugging out and dissapearing for 5 seconds when attacking something that has died isn't cool.

but I MAKE it cool thinking Yi dissapears into the afterlife just to punch them in the face one last time. That would take about 5 seconds. For Yi.