Having the longer tongue may cause that effect on the Jeep. The longer the arm, the more the center of gravity is moved aft. It's acting as a lever.
I'd go back to the original short ball mount, if I didn't make that clear with my earlier remark. Flipping it over ought to give him enough space to release the hitch lever. If it doesn't, just swing the spare tire a little bit out of the way, as GA_Boater suggested.