Load attached repro mission. There are three examples of undesirable behaviour:
1. The player starts near a small house with an AI subordinate. The house is surrounded by grass cutters. Order the subordinate into one of the house positions. Observe as he does not attempt to enter the house, but ends up standing outside it. Go back into the editor and move the grass cutters away from the house. Preview the mission again, order the Ai into the house, and observe as he enters through the front door as expected.
2. West of the player is a single AI unit who has a scripted order to move to a marker position on the road. Three grass cutters are in his path. Watch as he moves to his waypoint but completely avoids the grass cutters. Remove the grass cutters from his path and he will run more or less straight to the waypoint.
3. To the north is an AI unit in a house. Grass cutters are spawned here, one on each corner of the house, one in the centre (each is marked by a 3d arrow). The unit has the same move waypoint as the one on the road. Observe as he walks out of the house but is unable to walk past the point where the arrows are. He usually ends up running on the spot. If you move the waypoint marker slightly, this unit is sometimes able to escape the house.