Hive Onslaught Elite (HSE) has this objective: "Sustain fire (Keep at least 2 players alive)". However, HSE doesn't seem to recognize that even when HP of a player drops to 0%, that doesn't mean they're automatically dead. So for example when Continuity keeps you alive, mission still fails if your HP dropped previously to 0%.
https://www.youtube.com/watch?v=2u2_grrynjs
P.S. On another note, the Optional objective "Lose No Ships" doesn't seem to be registering as well, unless word "lose" means something other than dying or leaving map.