Load attached repro mission. An AI unit is assigned as driver of an empty Hunter, with a simple waypoint down the road. When you enter the game, the vehicle does not move. Go back into the editor and change the empty vehicle to another kind of MRAP or any other type of vehicle, then restart the mission and observe that the vehicle now moves to its waypoint.
Try also keeping the Hunter, but shifting its position slightly on the road. Sometimes this enables it to move.