I know you solved the problem with lubrication, but also make sure the chocks are tight to the tire. When you lift a trailer it does move a bit. If there is a slight incline or decline there's enough pressure at the coupler that it could make it stay coupled until the loud bang when the truck drops away.
2017 RAM 3500 SRW Laramie Crew Cab Long Bed w/6.7 CTD & Aisin
2015 Eagle 284BHBE Premier