AZ AKS Create command creates a new resource group
The az aks create command allows you to specify a resource group to deploy to. However, this resource group only gets the kubernetes service, the command then creates a NEW RG that starts with MC_. This RG does not have the same permissions as the originally specified RG and therefore the user cannot create additional services in the new RG, such as ALB or PIP.
Robert K. commented
It's worse, because one cannot access created storage accounts within that resource group MC_, which is basically required for support/ backup when you are using Persistent Volume Claim.