Haven defense mission missing resistance?

[Alex319]

I just did a haven defense mission where I had 10 resistance members in the region. The counter at the top on the mission showed all 10, but only 3 showed up on the map (they were all right around the start point; I searched through almost all of the map before the mission ended and did not see any more). 2 of the ones that showed up proved to be faceless, so I could only rescue one, and the other 7 were nowhere to be seen. What happened?