IssueTracker

Please provide as much information as possible. At least, this should include a description of your issue and steps to reproduce the problem. If possible please provide a summary of what steps or workarounds you have already tried, and any docs or articles you found (un)helpful.

Deploying an application with the following components:

* runtimeconfig.v1beta1.config
* compute.v1.instance
* runtimeconfig.v1beta1.waiter
* container.v1.cluster
* compute.v1.router

This is a private GKE cluster with Istio (based on official Istio DM setup + a router to access the internet).

Problem you have encountered:
After changing a parameter in the YAML file for the deployment (e.g. "preemptible: false" when it was "preemptible: true"), and after applying update+preview:

gcloud deployment-manager deployments update my-deployment --config=my-config.yaml --preview, all seems good and ready to be applied.

The fingerprint of the deployment is rX0Uowmd5F4dePNEDlwrBA==
Waiting for update [operation-1556543529276-587ab0823d262-362e4596-f49b2afd]...done.                                                                                                                                                        
Update operation operation-1556543529276-587ab0823d262-362e4596-f49b2afd completed successfully.

However update fails using gcloud:
gcloud deployment-manager deployments update my-deployment --config=my-config.yaml

ERROR: (gcloud.deployment-manager.deployments.update) ResponseError: code=400, message=Invalid value for field 'resource.target': '{  "imports": [{    "name": "istio-cluster.jinja",    "content": "{% set CLUSTER_NAME \u003d env[\u0...'.  Deployment in preview must not have a target with UPDATE

However deployment is marked to update in the google console, and can be updated successfully without any problems.

What you expected to happen:
Deployment is updated without problems from gcloud and console.

Steps to reproduce:
Modify GKE Istio DM from their package, modify a parameter from the YAML config file, apply preview and then update.

Other information (workarounds you have tried, documentation consulted, etc):