In the community crafted mode, I have constantly had people randomly drop dead. It shows they died in the kill feed to no one, and their soul disappears almost immediately. It seems to happen at random, several times a match.
At first I thought it was people who accidentally could kill themselves (Pharah, Ashe, Tracer) but then it happened to Winston, Rein, Venture, and Ana (and more). I haven’t seen anyone mention it though?
I read through the modes hero changes and seemed to find nothing about that being an intentional hero ability.