It is not unusual for my TT ball to stick. It seems to get hung up on the front edge of the ball socket.
Usually when I unhitch, I unlatch the ball lock down lever and jack up the TT tongue a little to take some of the load of the WD bars. Usually when I release the WD bars the ball drops free.
If the ball is still firmly jammed into the ball socket I can see the gap between the ball and lock down mechanism. It is about ½ inch or so. In that case I remove the WD bars, lower the TT onto the ball, chock the wheels and back the TV up a tad to release it. You can back up too far and catch on the release mechanism also.
I only jack the tongue up enough to reduce some of the down force on the lease lever but it is often enough to release the ball also.