Also when spraying rows you need to have the width set for the same as the spray is wide, no over lap, to get on the right row.  Forget about the light bar after you have turned around.  just follow the row.  only use the lightbar to get on the next pass on your end rows.  That is with Row finder and adaptive curve.

I have never seen your problem on any of ours. we run 6 or 7 of them here for fert and spraying. 

It just sounds like your not useing the right guidance for the job at hand. ie row finder.

Not sure if this applies but our "older" applicators when first started with light bars would still run foam and light bar.  They would still follow the foam instead of the light bar and then 3 passes later they would have big skips and overlaps all over.  I finally had to "break" there foamers to get them to trust the light bar.  Now they pretty much will not spray or fert without one!  But they still can barely setup the ab line!