To anyone deploying to App Engine or GCE having this issue I found a workaround is to use 'gcloud preview app deploy ./app.yaml' instead of 'appcfg.py update ./app.yaml --no_cookies --oauth2'
YMMV
And now, 5 minutes later, it's back.
To anyone deploying to App Engine or GCE having this issue I found a workaround is to use 'gcloud preview app deploy ./app.yaml' instead of 'appcfg.py update ./app.yaml --no_cookies --oauth2'
YMMV
And now, 5 minutes later, it's back.