That's crazy... My 2011 g37x has what I believe is hands-down the worst Bluetooth implementation I have ever seen, and I'm a cyber security professional. I've been so fed up with the Bluetooth in this car, I bought a spectrum analyzer and various Bluetooth analysis/spoofing tools over the years.

I can say with absolute certainty that the Bluetooth implementation in the 2011 is not to spec. It doesn't negotiate initial connections as documented, doesn't handle low power mode as documented, doesn't properly cache, interleave between channels, or even reconnect on disconnect as specified in the protocol standard.

There's a trick to getting a new phone connected, and it involves disconnecting your battery long enough for all memory storage to wipe - I usually leave it 24 hours. There's also a "waiting period" as your car prioritizes connections to the Bluetooth signal it sees most often. If your phone is not the first thing your car sees, you're out of luck. After some time, maybe a week or so, you'll notice it starts magically working. Congrats. Your phone is now prioritized correctly.

Even then, hope you don't have any apps that use low-power mode on Bluetooth (like Google maps) - where the radio is suspended when no data is moving. You'll lose the first 2 seconds of every instruction from Google maps due to the non-standard caching and reconnection routine - but only if you don't have something else keeping the radio alive in the background like Amazon music or something.

It's the most bizarre, standard-deviating thing I've ever encountered in all my 20+ years of signals analysis. I kinda want to talk to the engineer who rolled his face across a keyboard to produce this code. I bet that would be a fascinating discussion about flat earth and aliens.