No point in creating few tickets, so im gonna describe all bugs here.

1. mi8_rear_door ({558FDFA93A92EC0B}Assets/Vehicles/Helicopters/Mi8/VehParts/Mi8_door_rear.xob) uses wrong rig, and cant be parented to mi-8 itself.
2. Red star decal is "welded" to mesh, instead of being attached via slot. It gives modders less opportunity to mod this heli.
3. Because of, vehicle and vehicleSimple colliders, its impossible to use rear doors as intended. As possible fix, i think it might be worth either completely removing "doors" from vehicle and vehicleSimple colliders, or separating them and attaching to door bones.