It is very difficult to reliably reproduce since it happens randomly during every game - where there is a respawn / revive option but definitely seems to have something to do with respawn and the keyboard buffer and Arma3 key bindings. It seems that if you die and are either revived or respawn in game the key presses in the kb buffer continue to 'play out' once you are alive again. Almost as if on death the last key press is repeated in the kb memory for the length of time you are incapacitated. Anyway that is what we have managed to so far to ascertain.