It acts like the ICtrigger box is the overall collision box. It stops right on the edge of the ICtrigger, and if you move it forward a bit, it keeps moving until it reaches the next pole.
First time I saw any issues was on a turn. Right wide corner, had a pole right in front of it, and the sprayer would stop in the middle of the turn. I just moved the AutoDrive line, and it work without issue.
But when using the route in the image, it kept stopping for every pole it had on it's path.