Old car, no issues with FM radio. On my golf, local FM stations I get crackling every now and then. I'm guessing this is maybe DAB+?

Hi I have a 2011 Passat TDI with a RCD 510, Premium 8 radio. It worked beautifully until a month or so ago when it started a strange habit which is getting more frequent.
When I start the car in the morning, the AM stations are hardly audible (yes with the volume turned up), if I then switch...