This was never a thing in Arma, atleast for the many years I've been playing. It seems once a teammate is killed in game their dead body disappears, gets automatically deleted. This is extremely unrealistic. I'm not sure if it was already mentioned, or if a new feature was added to disable this, but I highly recommend to leave dead bodies as they are... on the ground where they died.

This issue can interfere with immersion, realism, looting, certain community scripts and mods when a teammate's body just vanishes after death.