If. You jacked up the body the air bags / level sensors would be extended, so sending a signal via the level sensors that the air suspension was too high/ over inflated , so causing the solenoid valve / pneumatic control valve to want to open and dump air
If this hadn't happened for a while it may not have reseated properly, so causing a leak on the control / solenoid valve.
X5 Salisbury had this problem and sprayed silicone spray into the valves exhaust and cured the deflation of the bags. I would show the thread but can't get my head around this new format.
Basic pneumatics, but I work in the compressed air/ pneumatics industry as a service engineer
Looks like the valve block is inside the dome on the boot adjacent to the compressor.
I also worked on Trucks and trailers in the 90's which used all around Air suspension, so a similar system.
Take hold of the level sensor control rods that fasten to Thea les and phisically lift them independently, if the suspension lifts and lowers as you move the level sensor, all is well,
If it goes down over night, and then lift on startup, looks like the exhaust on the pneumatic valve is probably passing
Hope this all makes some since as I've had a bottle of wine
