Hello,
I understand that you are having difficulties removing the custom domain mapping for your Cloud Run. I’ve noticed that you’ve already opened a case in our regular support channel and it is being addressed because it is related to your project specifically. The first step that is necessary is to provide a redacted debug output of your command so that we may look closer at any “hidden” errors. This is not recommended to do in Google Groups, because this forum is meant for general discussions. I see that your error is being investigated now and if you have general questions for discussions, I invite you to post them here.