Not really enough information for me to offer anything that might be helpful, Doc...
Skip or stick... those seem like two different behaviors... is it one or both? Can you see the lift cable where it comes off the winch, and is the cable loose? Is it dirty? Are the corner supports removed? (I know... had to ask). Have you tried standing in the open doorway, reaching up and pulling down on the top while an accomplice de-cranks?
And lastly, have you tried standing next to the pup and dropping something heavy on your foot... like, say, a hammer? You may have accidentally discovered a zero-gravity zone.
Michael, Suzy & Arnie Asada (Chihuahua)
'97 Viking Legend 2480
'19 RAM 1500 Laramie 5.7L Hemi