After the jogging section where you are reshown the targets you have previously shot down, you are tasked to shoot them once more. However, none of them fall down. They fail to fall at any range, from the shooting area to point blank.
To test that it was simply not dodgy aiming, after the jog I moved to one of the furthest targets and shot one of the npcs. Every time was a direct hit, prompting the mission failire screen.
Conclusion: Mission cannot be passed (for me) as targets do not react at being shot at accurately.