Who's fault is this crop injury?

Several weeks ago I had the local branch of one of the mega crop companies spray about 20 acres of orchard grass (and 10 brome) with 2 4D, banvel, and nitrogen, mostly because of a problem that I had starting with white cockle. The nitrogen was only 20 units. The spray rig came from another local farm where they were also covering grass hay.

When I began mowing yesterday I quickly discovered that I still had a white cockle problem and I also had a problem with horribly stunted orchard grass. Like a foot tall and some stretches of the field where it barely even shot any heads. One 6 acre field seemed to have the most stunting and least weed kill. The others cleaned up nicely but still seem somewhat stunted.

My sales rep is stumped. Does anyone have any ideas?

Who's fault is this crop injury?