I haven't had this problem since I avoid hitching up with the hitch ball all the way back in the coupler. I also started greasing the ball too.
I'm hoping the OP comes back and updates us. Inquiring minds what to know....
The day I took delivery of my TT I arrived at the storage place only to find the electric tongue jack dead along with not being able to disconnect. I had the same problem as the OP. My sister-in-law gave it a little gas and got the TT disconnected but also the coupler ended up with a dent. Since then I found putting the truck into Drive
(no gas/no break) is enough by itself to move the ball forward to disconnect.
Great choice for "Living within my means" and camping for one...
2011 Salem Cruise Lite 20RBXL & 2011 Toyota Tundra Dbl Cab
Camping History: 45 Trips / 133 Nights / 3736 Miles
FRF Social Group: Campers of the West