Carplay spotify music interruptions after taking a call

I have an Iphone XR, running IOS 18.0.1, I frequently play spotify via carplay, everything works well until I take a call, when I hang up, the music comes back on but it breaks up at regular intervals, e.g. it plays for a couple of seconds and then a second break then comes back on again. I have tried restarting my phone but this does not help, I have to shut off the car and then everything is normal again right up until I have to take another call then the process starts all over again. Any ideas?