from my understanding certain parts of the mesh are "ranked, or Scored" higher then others, things like roads are give in a higher "score" then a field, so yea sometimes it will take the longer path, because its ranked higher then the shortest path though the field or whatever, its possible that on newer meshes this hasnt been done yet, so you might have it run around a house. so yea, like tony said, if you could report issues like that to the thread he linked, we can work on scoring those area's so it doesn't react the way the drawing might depict.