You have a small leak. You should have it checked. Because if the leak is in an air bag it will only get worse. That's not a good thing when on the road.
Most likely it is a fitting or a valve leaking. But you need to know and get it fixed.
I have replaced three valves in the last three years and an airbag last year. (08 Winne) Two weeks since I pumped the system up, dumped the tanks and refilled the air bags and let it sit with no jacks down. It's just like I left it. Getting ready to go.
Resetting Auto Level System.........
Turn the coach ignition to the accessory position. With the coach in a level attitude press and
hold the ALL UP, BI-LEVEL FRONT and BI-LEVEL REAR buttons simultaneously. You should
hear an audible beep. Turn the control ‘on’ and all four indicator lights should now be lit
indicating the level sensor is showing the coach to be level. If all four LEDs are not
illuminated, repeat last 2 steps. (NOTE: Coach must be level first.)