Carplay used to show split screen, and now won't

Hello!

I have a 2017 Mazda 3, which I upgraded to include Carplay. When the new split display was released, it showed up in my Carplay, and I was getting very used to it. Then one day, it just stopped doing the split screen. It does the old "classic" view, but not the split one. I've updated my iPhone 7 with the most recent version of the iOS, and it still doesn't do the split display. However, when I had the car in today for routine maintenance, the guy who was working on it connected and got the split screen. Also, I have tried Forgetting the car, so that I could re-pair the Carplay and see if that fixed it. However, even though it takes the name of the car out of the Carplay settings, the minute I take the phone to the car and connect it to the USB port, it automatically connects Carplay as if it had never Forgotten it! Does anyone know what's going on and how to get the split Display back? Thanks!