I might be going crazy but since the latest update it seems like apple car play screen as a border around it that it didn't use to have?? I swear it was added and I dont enjoy the looks of it compared to the older way it was displayed.
I had the EXACT same problem as mentioned above. The paperwork when I got it back mentioned something along the lines of removing heat shield and plugging in plug into correct socket. Fixed everything. Looks like someone on the assembly line just said “F it” to that part of the job!