Rear adaptive suspension

[skitts7]

Good afternoon 

I have recently purchased a c6 allroad avant 2008 the rear suspension drops right down on both sides when left for a few hours

When i start the car both the yellow and green warning lights flash and after 1 minute or so they go off and the car is at the correct hight and seems fine 

Today i put it in jacking mode and left it for 4 hours but when i came back the suspension was low again 

This only happens at the rear 

Everything else on the car seems fine

Any ideas

Thanks