Create cluster success in UI but got ResourceErrorCode

Hi there, I encountered similar issue as this: https://github.com/GoogleCloudPlatform/deploymentmanager-samples/issues/148

I'm using https://github.com/GoogleCloudPlatform/deploymentmanager-samples/blob/master/examples/v2/gke/python/cluster.py and based on my recent changes https://github.com/GoogleCloudPlatform/deploymentmanager-samples/pull/536 to create a GKE cluster.

My cluster is created successfully as least on the UI part.

But in the terminal, I got the following errors:
```
Waiting for create [operation-1581380209089-59e41c59e1bfb-c62501e0-2a81feab]...
failed.
ERROR: (gcloud.deployment-manager.deployments.create) Error in Operation [operation-1581380209089-59e41c59e1bfb-c62501e0-2a81feab]: errors:
- code: RESOURCE_ERROR
location: /deployments/carolyn-manager/resources/carolyn-manager-3-cluster-py-type-apps
message: "{\"ResourceType\":\"deploymentmanager.v2beta.typeProvider\",\"ResourceErrorCode\"\
:\"DESCRIPTOR_URL_FETCH_ERROR\",\"ResourceErrorMessage\":\"location: /typeProviders/carolyn-manager-cluster-py-type-apps->$.descriptorUrl\\\
n\\\"{\\\\\\\"originalResponse\\\\\\\":\\\\\\\"{\\\\\\\\\\\\\\\"paths\\\\\\\\\\\
\\\\\":[\\\\\\\\\\\\\\\"/apis\\\\\\\\\\\\\\\",\\\\\\\\\\\\\\\"/apis/\\\\\\\\\\\
\\\\\",\\\\\\\\\\\\\\\"/apis/apiextensions.k8s.io\\\\\\\\\\\\\\\",\\\\\\\\\\\\\
\\\"/apis/apiextensions.k8s.io/v1beta1\\\\\\\\\\\\\\\",\\\\\\\\\\\\\\\"/healthz\\\
\\\\\\\\\\\\\",\\\\\\\\\\\\\\\"/healthz/etcd\\\\\\\\\\\\\\\",\\\\\\\\\\\\\\\"\
/healthz/log\\\\\\\\\\\\\\\",\\\\\\\\\\\\\\\"/healthz/ping\\\\\\\\\\\\\\\",\-bash: Waiting: command not found
```

Could someone explain why if there is an error my cluster can still be setup? Or is there any special requirements that I need to set to avoid such error?