"We are investigating an issue with Google Kubernetes Engine node pool creation through Cloud Console UI."
So, it's a UI console issue, it appears you can still manage
"Affected customers can use gcloud command [1] in order to create new Node Pools. [1]"
Similarly, it actually was resolved in Friday, but they forgot to mark it as so.
"The issue with Google Kubernetes Engine Node Pool creation through the Cloud Console UI had been resolved as of Friday, 2018-11-09 14:30 US/Pacific."