Tryndamere Ult Bug

I main tryndamere and have missed my fair share of ults. You know you missed it when you're dead and the ult isn't on CD. This time, I died and my ult went off right after I died. I doubt this is intentional and just think it's some kind of weird bug. Only happened once today 4/14/16 and never before this. I actually heard the sound of his shout when he ults after the screen went to gray. The ult just went on CD as I died. I'm 100% sure the ult didn't finish, and then I died. Anyway, just wanted to report some kind of strange, probably rare bug for your review. I'm sorry, but I don't know how to reproduce it. Perhaps it had something to do with an interaction between champion abilities; that would be my best guess. Enemy team: Janna, Trist, Poppy, Malz, Yi. Ally team: Cait, Mao, Kat, Morg, Tryndamere. Wish I had more info to share. Thanks