There is a 'Google Cloud Service Health Updates' Slack app that has notifications about this incident. Here's what it looks like on our channel:

    8:18 PM
    APP UPDATE: Global: Google Kubernetes Engine Nodepool Upgrade Failures
    Incident began at 2023-10-02 11:29 (all times are US/Pacific).Summary: Global: Google Kubernetes Engine Nodepool Upgrade Failures
    Description: A mitigation has been rolling out and we are assessing its effectiveness. We will provide an update byTuesday 2023-10-10 12:00 US/Pacific with current details.
    Diagnosis: A small number of customers are experiencing failed nodepool upgrades. Customers experiencing this,  may see "Internal error" in Google Cloud Console. Retrying is suggested but may...

There are quite a lot of alerts about various issues.