I have seen this quite a few times in coop mission escape from stratis when you resume and you are close to alert enemy soldiers.
While the savegame is finishing loading and still showing the loading screen position reports will start coming in and you can hear your player running around and shouting but the game is still loading. This results in the player engaging the enemy or taking fire and getting killed without you being able to do anything and could potentially result in situation where you cannot resume a savegame because each time you die and have no control over it.
Same thing happens if my friend enters the game after me. I can see his player running around under AI control.
So it seems that AI control of the player should be completely disabled while loading or even better, the player should not appear until the loading of savegame is completely finished.