As a result of my own shoddy positioning, I fell into one of the pits on the Gauntlet as a meched D.va, A downed state baby D.va then respawns directly on top of the pit she just fell in and plummeted again, with no way to reposition onto solid ground for a rez. After a couple cycles of this, the screen fades to black, no voice lines can be played, but attempting to move plays very slow footstep sounds - most likely from being in that downed state. The fade to black persists in the replay, even in third person mode. Spectating my teammates revealed that a downed baby D.va was indeed spawning at the top of the pit and immediately falling in on an endless loop.
There was a brief window of time when a new wave was starting and when the lid of the pit was repairing where you could try to clamber onto solid ground, but being unable to move while the screen was fading back in and during the first part of the downed animation means that your window of time to move and recover seems to be about a second.
Also, this faded to black state seems to completely bug-out the replay viewer. When spectating myself in this fall-locked state, I lost access to all spectate controls and could not open the game’s menu with Esc