it happened to me while on a ladder.

maybe it's tied to the rubber banding bug issue, like, the engine doesn't understand your vertical position but 'fixing' that instantly kills you.

maybe. :p

happened in Cherno climbing ladder on to the highest climbable (industrial) building in town.

Was climbing up (about 1/3 of the first part) and double pressed alt so I could look left for screenshot while climbing. (you can't steam screenshot while alt is pressed, so double alt is the only way to take as screenshot while alt-looking as you won't have to keep alt pressed).

Anyway, I turn my head right, ready to make a screenshot. You are dead.

No sound, nothing. Just that. I pressed esc and I see myself in the grass (blackscreen dissapears for one sec if you 'esc' in and out of the game.