There seems to be widespread issues (across the board) with GM rear entertainment systems in the new MY 2021 SUVs. Many individuals are experiencing connectivity issues while others just can even turn on their screens. They are basically dead. GM is aware of the issue and unfortunately do not have any fix for the problem. Customer service has been worthless. If you have any issues with your screens, MAKE SURE you carefully follow your state'* lemon laws as I am certainly not confident that the issues will be resolved. I could be wrong, but not looking good based on my research and also what I am being told by GM. Updates to follow.

Well this sounds interesting. Have you contacted GM Care Center & filed a complaint regarding the rear entertainment center? https://www.gm.com/company/contact-us
With such a new vehicle, it may take some time for GM to sort this out & hopefully have updates/fix available.
Feel free to let us know if this issue does indeed get resolved.

I'm curious how many cases we are talking about here.

I was told by a GM rep that there are more cases. Not just an isolated incident.

Yes, customer care was worthless. They couldn't have cared less. After jerking me around for a week, the simply referred me back to the dealership (even though I clearly explained to them that the dealership was telling me "NO FIX AT THIS TIME".

Sounds like Lemon Law time.