CarPlay connecting intermittently

[cdrake]

I recently purchased a new 2019 Sierra SLT Texas Edition on 12/20/19. It was a demo model so it had about 3500 miles on it when I bought it. Everything was working fine until last Monday 1/6/2020. I drove to work that morning and CarPlay was working fine. Later that day I went to lunch and CarPlay was not working properly. It would connect for about 10 seconds, then disconnect for about 2 seconds, then reconnect again. This cycle would repeat over and over again. So first I Googled the problem and went through all the trouble shooting steps. I reset my iPhone multiple times, tried out different iPhone cables, plugged into the secondary USB and USB-C ports, reset the settings on the Infotainment Center, etc. So then I took it into the dealership. However, when the service technician plugged in his iPhone, CarPlay worked perfectly. I was able to use CarPlay in the loaner truck that the dealership gave me without any problems. Since then I have plugged in my wife's iPhone, my work iPhone, and a friend's iPhone. All 3 have worked fine with CarPlay. I've also been on the phone with OnStar and Apple. OnStar wasn't much help and I'm currently waiting for the diagnostic results to come back from Apple. Has anyone else had this problem? All my devices have the most current software update. IOS version 13.3 and and Infotainment System Update v805.1. 

[afterburner82]

Just got a new 2020 3.0 diesel.  Plug my phone into CarPlay and the screen stutters like it is super slow moving from music to maps, touchscreen takes 10-15 seconds at times and when on music, it shows it is playing but no audio from the speakers.  Running an iPhone X.  Current IOS.  Took it to the dealership, the guy plugs in his iPhone 6s and it plays like there is no issue.