Hi there,
so, in todays (2024-04-01 - 2024-04-02) Sortie 3 Mission (Defense), while in solo mode, it is impossible to revive the defense target when he goes down (it's... so called a.i. making this even more likely).
i tested this in several runs, no option to revive or anything. neither in warframe nor in operator. i was not afflicted by rad status (and as far as i can tell neither was the defense target in all my tries)
so i had to do this mission in public mode (where he was revivable actually when he went down)