612 Bose radio will not switch stations

Hi all, just noticed during a traffic jam that the Bose unit in my 612 OTO does not change radio stations.

If you turn the knob and then select the radio station you want to hear, the newly selected radio station appears on the screen, but you continue to listen to the same previous radio station.

If you select AM to FM and FM to AM, press Traffic or Scan, nothing happens as well: you continue to hear the same radio station with no interruption in the sound.

The preset buttons on top (1 to 6) also change the radio station on the screen, but what you hear remains unchanged.

Any hint on what might be?

Thanks.