Lux's R- Final Spark animation

I've just recently played a one for all as against and i have noticed that her ultimate- Final Spark's damage is coming before the animation. For example, while i was playing, i dodged a lot of ultimate, when I was caught in her Q- Light binding and I saw the light of her ultimate and died, and then i saw the explosion of that ultimate, to be sure i saw my death recap and it showed that I died for that ultimate. Later in the game i saw my teammates playing and almost the same happened to them while a lot of ultimates where being channeled. The reason I think this may happen is either a problem in the animation or a bug when many ultimates are used. This is an important problem because it makes almost impossible for people to dodge ultimate in one for all.