I had another mission where the enemies immediately see you from the start. Actually, I got it twice at the same time; two pods of enemies activated, starting me with 6 active (and fairly strong) enemies. I got it on video. Here is the amusing footage:
https://www.youtube.com/watch?v=Pz_PJbRSsD4
So I got the Instant Enemies bug again
Re: So I got the Instant Enemies bug again
"At least we know where they are!"