MH-9 helicopters piloted by nato ai will abandon travel toward assigned waypoints and hover near ground units that are firing upon them, almost as if it thinks it's going to attack them. The trigger for this behavior may be the wounding of one or both of the pilots, as setting allowDamage to false does not prevent the problem. The problem seems biggest in areas of the map where the helis must take off and move slowly due to very hilly terain, such as traveling from Camp Rogain to the Air Base, but is less noticable near the airbase itself, or when the MH-9 has significant velocity.
The civilian version of the Ka-60 does not seem to display this tendency as much, though it will abandon its waypoints as well with sufficient fire, but will typically keep a good distance of nearly a kilometer away from ground units trying to engage it.
Interestingly, the AH-9 doesn't seem to display this behavior at all. It will gladly roll right through heavy fire, land, and sit where you told it to. Maybe the MH-9 and AH-9 scripts got switched accidentally? {F18122} {F18123}