Assuming no leaks, with engine running & door open, the pump should run and fill the tank until the pressure switch triggers. Also the height switch should be lit but not flashing. Then when the tank is full, closing all doors & tailgate allows the system to adjust. Occasionally the height switch will not change state to flashing (adjusting), but I never figured out exactly why this happens.
Quick check on the height sensors is to set each height manually (Access, Motorway, Normal & High Mode), and note the readings for each. If any are wildly out from the expected values then you might have a height sensor issue, but unless the tracks are dirty & housing is leaky then you're probably ok. As said earlier, gently moving the sensor & watching for jumpy readings is the proper way.
If the system still hunts up & down with the car level & parked, you still have leaks somewhere, either in the pipework & joints, or inside the valve block. Given that you have one of Kurt's valve blocks the Seals, Valves & NRV's should all be good & prevent internal leaks.
Mine does hunt up & down a bit when stationary, mostly at rear, but in my case there is a small leak through the Inlet & Rear valves inside the block. This causes the rear to rise slowly between each ECU adjust cycle, but only about half inch. Not noticeable while driving though.