Apple CarPlay takes over Toyota

In the past 6 months or so this problem has begun. When using my iPhone 12 Plus Max with either of my Toyota vehicles (2019 Camry or Rav4) and connected by cable to the car using Apple CarPlay the phone controls the audio source. I can have the radio playing and select a weather application and it suddenly changes the audio source on the car to the phone. In fact, many apps will do this including Facebook. I just select Facebook on the phone and it switches my car audio source from FM to the phone and I must go back into the car configuration and switch it back to FM. Of course, I don't use Facebook while driving but just using that as an example. It perhaps seems any app on the phone that uses or can use audio will cause the car to switch over to the iPhone for audio. IOS 14.8. It does this on both vehicles and with two different iPhone 12 Plus Max phones. I've searches on google for this problem and seems it has been happening to some extent on multiple phones and car brands for a while but only recently has it started for me. It's pretty annoying if I have my phone connected and someone else is driving and I use an app and it switches the audio from FM to the phone... Any ideas?