carplay iOS18 audio source

Since upgrading to iOS 18 my CarPlay continuously changes the audio to CarPlay on start up. It used to stay on what it was, in my case the radio of the car. Now I put it back on radio and look at the Waze map by going back to CarPlay. After this the audio of Spotify doesn’t come through when I want to listen to that. In iOS17 all these things worked as should.