Hello,
what basically happened was that when I died fighting Izual with Barbarian, he was very low on health and died just seconds after me because of a bleed/poison effect. I respawned then and acquired the kill. I am not sure if this is an intended effect, thus I am mentioning it, for this may be a new information for you.

I am curious though, if you find time to respond even with just one sentence whether this effect is intentional, I will be mostly pleased.

Thanks for reading