That probably means a small leak somewhere, if you are confident that you don't have a leak in any of the pipes or fixtures it is probably the check valve in the pump. My class A had this for years not a big deal.
Assuming you have a gravity water fill you can fill your tank then connect to city water. If it is the check valves your tanks will over flow in a while, it could be minutes to hours to happen. If it overflows either replace the pump or leave it like I did. I assume the pressure fills have an overflow too but I not familiar with them.
TT 2017 Flagstaff 831CLBSS Classic Ultra lite
TV 2017 F150 6.5' bed 3.5 Eco-boost
prior TV 2014 Silverado 2500 HD