Yes & Yes. Support the coach on its hydraulic jacks if it has them, to provide support when the air bleeds off. Coaches with air leveling will have an auxiliary pump to replace the air loss.
Air bleed down may take anywhere from hours to days, depending on how many leaks there are in the chassis air system. They all develop leaks over time and need some extra attention, or you can just live with it. It doesn't hurt anything as long as the leaks aren't severe enough to tax the engine air compressor .
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL