I don't have it recorded in a video, but yesterday I died in a weird way like that, but the animation the played was the stabbing. I was against only one Zed, I've front attacked so it gets stunned and then stabbed him. The animation played normally and when it was almost finish (I was expecting the sound of kill), then it just turned (really fast) and bit me.
Really odd. Don't know if it was because of that too.
Also, as you've shown on video, for me at least, it's clearly a bug.