Crito

To me this looks like delamination from improperly mixed carbon-ceramic alloy. You might want to pick a different manufacturer for the replacement rotors.

Faast

First and foremost, you need to find out the root cause of the problem before you address the issue or try to move on. Chances of having both rear rotors damaged by faulty installation seems bit odd, I am linking few CCB resurfacing companies who can fix the rotors at a pretty decent prices. It won't hurt to at least get a quote and ask them what could have caused the problem so we can all avoid that in the future.

Pros of owning a car with CCB easily weighs out the cons. I will always have the CCB's where ever I can get them. I am currenty in the market for a Porsche and finding one with the ceramic brakes is on the top of the list

https://rebrakeusa.com/refurbishment

Hope this helps