I had exactly the same problem. The dealer solution was not adjusting the height sensors. It was replacing both of them for brand new ones. The height sensors are known to go bad. Luckily I was still under warranty. I remember the tech saying that it was not safe to drive a lopside truck.

 

You have to check before any adjustment if the sensor brackets are not bent or cracked.
Is I just found out, my sensor was hanging from upper control arm because the sensor arm/shaft is very hard to move, rocking the bracket up and down instead of sensor shaft rotation cycle.
I'm in need of left or both sensors, if any of you have a used set for sale, please let me know.
Thank you and good luck GX-ing!