Music switches to Telephony audio in cars!

I’ve been experiencing a strange audio problem when my iPhone 13 Pro is connected to a car for music by cable.

The best way I can describe the issue, is after driving for a few moments listening to an audio service (Spotify, Mixcloud, TuneIn) the audio switches from the main music output to use the output which is for phone calls.

The music, or podcasts goes from a rich audio sound to sounding very tinny, usually quieter (as the volume set for phone calls is different). Sometimes it reverts back of its own accord, but usually to remedy the issue, I have to unplug the phone and reconnect. This seems to fix the issue, but it can happen again.

My initial ideas, were that this might be a cable issue, however I have tried numerous cables including generic ones, MFi and official lightning to USB-A. To add even more complexity the issue happens in different cars! I’ve experienced it in a 2021 Volvo XC40, 2020 Mini, 2022 Toyota Yaris and a 2020 Toyota Corolla. All cars have Apple Car Play.

The last thing to rule out, is a full maintenance of the software on the iPhone itself. I’ve had the problem ongoing for over 2 years now and maintaining iOS on most recent makes no difference.

I am wondering, before I visit a Genius Bar, whether this is a known issue and whether anyone can provide a way to fix, or if this is something I am going to need to get reviewed at an Apple Store?

Many thanks in advance, happy to answer anymore questions if required.