Karthus Passive: Q gets interrupted moment before disappearing
I'm putting it into gameplay because I'm not sure If it's bug. I'd not say so.
Karthus' Q says he detonates an area after delay. If I understand it well, that means it's not a channel. It has cast time, but you can do other things before it bursts. So once you give command to cast it, it should be casted. And yet If you cast it while on your Passive moment before disappearing, while you can see it is going to be casted by starting animation, it gets interrupted and the area doesn't burst. It starts glowing like about to burst but won't proceed.
The only thing that comes to mind is that it still was on cast-time and as you disappeared it got interrupted. But sometimes it really looks weird like it should have been laid. Is this right or does anybody else feel like it's a little inconsistent? I'm really not sure with this.