Bug With Map In Csx Heavy Haul

Another map bug or glitch where you can go behind invisible walls(which all over the map)
Picture 1: Location
When we find some of these rocks near to fence here:

Picture 2: Exactly place of bug
And then we just come very close to fence and we get behind map:

Behind this fence you can go on a beautiful hill

 

There a few invisible walls in certain spots in which you are to go out of the main area of play.