The suspension in the right rear wheel drops, pneumatic Audi A6 C6 Allroad

Hello.
I have a problem with pneumatics in the Audi A6 C6 Allroad 2008, namely:
The suspension in the right rear wheel drops from time to time.
Once I drive a week and nothing, and then it can fall several times a day.
I get into the car, the green indicator light from the pneumatics lights up, picks up the car and goes out, in the wheel when you start to hear slow cycling.
While driving, etc., the indicator light never lights up.
Now I noticed that it falls on the COMFORT option, when I leave on Allroad there is no problem.
What could be the reason???

I rode the Touareg '03 and for me the front left wheel dropped down, I thought a hole in the bellows but it turned out that the valve between the pipe and the bellows (looks like a nipple sticking out of the bellows and a screwed inlet pipe for compressed air) fell down regardless of the selected suspension option. Replacement of the valve and suspension calibration was enough here.
the pneumatic system itself is not complicated, the compressor bellows wires and the controller which is responsible for car maintenance, its leveling, etc. ... I think that either the level sensor has run out or you have a leak on the road compressor - bellows of a given wheel