I have a Kenwood DDX6705S installed in a 2013 GMC Sierra 2500HD. I connect to it with my iPhone 11 using CarPlay.
A few months ago I had odd problem preceeding the one I'm submitting today and believe it is somehow the root cause of my current problem. The preceeding problem was that one day Pandora would not work. The reason was that my iOS app had logged out and now wanted me to relogin. Problem was that it would not accept my password or a password reset. A couple days later all of sudden Pandora starts working logs me in with my original password and "Bob's Your Uncle!" Pandora starts working again.
After the above incident I now have a random issue where there will appear to be two Pandora streams running while using CarPlay. One shown on the Kenwood and the other on my iPhone. The odd thing on the Kenwood is that when I select the Pandora "Station" option and station display starts to rapidly cycle through different music artists without stopping and playing them. It will eventually stop but, if you select play it will repeat the same behavior.
In the meantime, my iPhone 11 is displaying a totally different station / artist and song at the same time connected to CarPlay. If I select "Play" on my iPhone, not CarPlay, it will always override the Kenwood Pandora stream and start playing normally from my iPhone through CarPlay. When I use my Pandora standalone without CarPlay I have no issues. and no issues when using Pandora with Bose Soundtouch.
All of this somehow to me relates back to the aforementioned password / login issue glitch. Has anyone experienced this or have any ideas of what's going on?
P.S. One thing that I know for sure if your having connections issues with CarPlay check your connection cable. I had an two iOS aftermarket charging cables that worked for a while, then intermittently, then nothing. I switched to a genuine Apple charging cable and haven't had a problem since. You get what you pay for! The root cause I believe is the connector or cabling close to connector. It the connector appears to get too loose when plugged in or the cable stressed at cable to connector.
Moderator Edit: Edited title for clarity