Lwiddis wrote:
“…looks like it leans back.” Have you checked the inside camper floor and the fridge with a level?
Has nothing to do with being actually level. OP is saying the camper isnt parallel to the top of the truck bed.
For this to occur, either depth of truck bed is not consistent front to back with respect to the top rail, or depth of camper from bottom surface to wider portion that overhangs the bed sides is not consistent F to R.
Or the bed is crowned. Few minutes with a tape measure and possibly a string or straight edge will definitively show where the perceived issue is.
But unless the bed is crowned, it is simply appearance and not a physical problem.