I checked the two front lines at the control valve, next to the accumulator and could not find any leaks. The next step is to check the line connection on the top of the airbags for airleaks. If there is nothing, then the only culprit can be the airbag itself that is leacking (slow puncture).

I am afraid to use the car at this moment as the movement on the airbag can sqeeze air through the small punture and the pump keeps on working to compensate - it may burn out.

What puzzles me is why is the car dropping in front to a certain level and then it settles. Can it be that the small hole in the bag folds to a point where it seals and why both sides?