I just installed an AVH2550NEX. When I use my iPhone X running iOS 12.3.1, the icons down the left hand side of the CarPlay screen are very slow in responding. When you hit the button, it flashes as it recognizes the touch but takes hitting it 10/12 times before it actually switches to that app or the home screen. The screen is responsive on all other place. I have tried using different model iPhones from the family, some running the same iOS and the unit works just fine. I have updated the firmware to current, used Genuine Apple lightning cable, rebooted and completely reset the iPhone and have seen the same issue. Any help is appreciated.

Bill

Do the update on the radio

Thanks for the help. By update do you mean the firmware or something else? I have updated the firmware to 8.10 and confirmed that after the update by reviewing the system info. Unfortunately it did not resolve it.