What you're likely seeing is what happens geometrically when all passes are done with autosteer but not all the same heading. 

Same thing is seen when you plant beans at an angle into corn stalks. Or lots of other cases. You see "waves"  where the planter or NH3 or anything is going between or into rows all at the same time across the bar or planter. If you view from another angle it lines up. Kind of like grave stones at a national cemetery