First, the flashbang I threw right onto the heavy did nothing. He stuns me anyway.
Second, my reviver never even had a change to do it's job because someone somewhere designed this game so I never get to be "downed" or "unconscious" in this scenario. Heroic with directives on solo is hard enough without losing a ton of progress each time these bugs happen.

https://gamerdvr.com/gamer/sojourner-eo/video/95468163