[dsttexas]

In my experience, the best procedure to disconnect and avoid this is:

1. Pull lever back and pin it in open position.
2. Raise trailer so there is about 1/2" open clearance between bottom of trailer hitch pad and truck hitch pad. So no weight on the truck.
3. If there is any resistance on the pin being let loose from the jaws, gently move forward and back a little.

Works every time this happens. Usually when trailer is slightly side to side in a different position than truck.

When I connect the trailer, I also get close enough to set trailer height so there is same 1/2" or less clearance between pads.