[GAMEPLAY] Graves' Smokescreen dud w/ incorrect ability channel time (Flash Frost)

When casting Smokescreen with graves, the ability goes on cooldown but does nothing (no visual smokescreen, and no effect) I have had the bug happen before but only once while recording:

https://www.youtube.com/watch?v=enI153I_09w

Note that the a channel time for "Flash Freeze" happens immediately after the channel time for smokescreen.

I tried to reproduce the bug but could not, I don't know if there is any way to deliberately cancel an ability with no "real" channel time.