Interesting. Then set it to transport mode. By doing that it will go to regular ride mode after unhitching, I don't like that. Believe me your issue has NOTHING to do with your hitch.
Are you lifting your truck? Pay close attention to when there is a small gap between the kingpin and hitch plates. are you using a 1/4" lube plate? If so buy a Hensley or any 1/8" plate so you can see when you have taken the weight off. I know the Tire Jack mode works, so I am thinking some of the other things I mentioned will help you.
Report back!