FO2 Rear suspension sag?

This is my first BMW and was purchased one month ago from Manhattan BMW. After sitting overnight, the right rear suspension sags/drops. It seems to be about 2-1/2 to 3 inches lower than the the left side. After starting the car it does rebound, but still seems to be a bit lower than the left side. The car has 13,500 miles on the odometer. Can anyone offer insight on this issue. I know I am going to take it for service. I was hoping to be more educated on this problem before I speak with a service advisor. Any advice, thoughts, help on the issue would be greatly appreciated.

Harry
2009 750Li-Sapphire Black/Black Napa-ZSP,ZLS,ZPS,ZCV,ZDA,610,ZCE,4U1,655,6NF,4CA

I think I recall hearing someone have this problem a long time ago, but do not recall what the issue proved to be.
Try doing a forum search.
My guess would be some kind of malfunction with the self leveling rear suspension.
Sorry can't be more helpful.
Please keep us informed of what you find out.