This weekend's experience: After cleaning up the coupler and applying a generous amount of grease to the hitch we headed out to a friend's place to do some suspension work on the camper. Parking there required backing down his driveway and turning to the right to get the camper level (truck was still nose up attitude and at about 30+ deg angle to the camper. After chocking and removing the hitch bars I attempted to unhitch. Had to goose the truck forward in order to unlatch the coupler, then roll back ever so slightly to reduce the tension on the front of the coupler and step on the bumper to separate the ball and coupler. Given the vehicle attitude and slope it didn't seem like an unreasonable effort to separate them. No sudden jump or lurching of the trailer.
On the return trip I backed up my sloped driveway and maneuvered so that the truck and camper were as straight in line as possible, put the truck in park, applied the parking brake and chocked the camper wheels. After unhooking the hitch bars I lowered the jack, released the coupler latch and raised the jack. The coupler came right off of the ball without issue.
Problem fixed? Maybe. Dumb luck today? Probably. Do I have a better understanding of what's going on? Definitely.
Your mileage may very.