My car is an April 2015 S85D. I have NEVER had the air relax after parking. I have parked for days with the air at Very High. I would consider it a defect to be fixed if the air dropped down after power off.
I usually leave the air controls screen up when I park...I do see shows the 'normal' setting when I first power up the car getting back in....and then it realizes the system is at Very High and changes to Very High on the display instantly.
Perhaps this is confusing people?
For some the problem is that while it stays at very high while parked, when you get in the car and it powers on it lowers the car without any manual input to lower. Instead it should stay up. that's the issue.