Hitch will not come off the ball.

I am sure this is nothing new to you old timers. We purchased a 2010 Dutchman lite and when we hauled it home we unhooked the torsion bars etc. lowered the trailer, slid the ball lock free and cranked the trailer up to take it off the ball. Unfortunately the ball would not come loose and I was only jacking the truck up with the trailer. It was like the ball was jammed into the front part of the hitch.

I looked under and the hitch lock was clear but again, the ball seemed to be stuck in the front of the trailer hitch. It took several attempts but by rocking the truck slightly, with just a minimal amount of crank pressure lift on the ball, the ball moved enough to crank it free.

Today I pull the trailer up so we could get ready for a trip south and the same thing happened. The ball is well greased. The trailer is new to us but the one I rented previously did not have this problem.

Any suggestions? Am I missing something? Do I need to hike the truck up higher?