A question about zed.

So, ive noticed while playing Zed that sometimes your ultimate's shadow is left in place if you die shortly after throwing your ultinate. This has happened to me a few times and am wondering if it is bug or if it already know. The shadow works as a free ward, and it lasts the remainder of the match. I am not sure if it works every time, as it only happened to me a few times so far. I dont know if this is important, but I found it useful. (ps, I'd love to be in PBE)