Radio problem M 6 GH

Hello, since a few days I have “loudness fluctuations” in the playback of radio stations. As soon as the car is half warm, the speakers get off irregularly left or right or center ;-(( When playing via Bluetooth – no problem. Does anyone know any reason? Greeting Heiko ps – the airbag lamp lights: 1x pause 2x pause and the whole thing then in continuous loop ;-(((