Nasus' Siphoning Strike sometimes goes on cooldown without triggering its effects [GAMEPLAY]

If a unit dies just before Siphoning Strike's damage goes off (when Nasus is mid-swing, basically), sometimes the buff is consumed without actually dealing the damage or rewarding any stacks. This happens even if enough damage would have been dealt to one shot the unit in question were it at full health, and whenever this happens the Sheen (or similar) buff is not consumed, so it seems to be a pretty subtle timing bug. Kill credit is not rewarded in these cases either.

I can probably try to reproduce it in a practice game and upload a video if it would be helpful, but I suspect you can reproduce it just from this description.