I’ve tried the mission a few times with different odds, and every time I’ll have issues with enemies being glitched up in the floor or in walls, but especially at the end of it, where I killed everything, but the mission won’t register as complete. I use Wolf and Saint (and homing ammo) to try and seek out anything I can’t see, Wolf keeps saying Green Across the Board, which usually means there’s nothing to fight. I have combed through that entire area. Nothing.
I see that this is in the PS4 forum. I play on PC, and while I have only played the arena like three times at the time of this post, I have noticed a couple enemies drifting into the floor (UBA Trojans mostly) and walls (little viruses). They have all managed to free themselves, but I had chalked it up to playing with Physx on high. I haven’t come across an issue where it was a game breaker though.
Thought: did you freeze a flying enemy off the edge of the map? Freezing a UBA Bug (for example) will cause it to fall, and if it’s not sitting over the map, I don’t know how far down it has to go to die… maybe too far? If it thaws before it dies, it could be out of range?