Seen some Range Rover's leak air only in standard height or access. Maybe set the vehicle to another height and try again with the battery overnight or remove the ecu power (fuse).
I use a tape measure in mm's at each wheel arch to ground.

 

I realize that this is a common issue with a couple different manifestations. I'm trying to understand why my 2006 LR3 settles within 30 seconds after turning the ignition off. I've been trying to find a pattern but sometimes the front (both sides) will settle, sometimes the back. Could it be bad valve blocks? I've also noticed it settling at stoplights as well. Could it be doing this as I drive as well? Any thoughts on where to start?

 

How much does it settle? I believe all EAS systems "level" themselves when a discrepancy is registered. My truck always gives a short burst of air shortly after I shut down the vehicle. Unless it is dropping a lot, I would say it's normal for the system.

 

I've been trying to catch it in the act with a before and after measurement. Eyeballing it it looks like 1/2 in to an inch. More than I would expect to be normal.
Another Q; Are there any standard "backyard" height measurements that one could compare one car against another? I know there are technical measurements from suspension parts to other parts but I'm thinking of the distance from the ground to the top of the inside of the wheel arch, or from the center of the wheel to the top of the inside wheel arch...