Just a couple more possibilities.
I noticed that you have the happy jack tie down system, you may want to check to see if your camper front bumper protection is hanging up on top of your front happy jack mounts. If that is the case when you get close to the front pickup bed lowering your camper jacks and the bumpers under the front happy jack bar, you may be hanging up on the bar. Instead of the bumpers previously mentioned, you may be using a 2X4 spacer up front, it could be falling down or your bed mat is pulling forward.
Of course, your camper could be tapered by design as already mentioned.