I'm trying to use the Cloud Composer to run my workflow. I wanted to use "GoogleCloudStorageToGoogleCloudStorageOperator" operator which is available from Apache Airflow v1.10, but not being supported in current cloud composer (it supports only Apache Airflow v1.9 for now (2019/01/16)). 

Following the guidance of the [Google's blog post](https://gweb-cloudblog-slim.appspot.com/blog/products/data-analytics/how-to-transfer-bigquery-tables-between-locations-with-cloud-composer), I added the operator to a cloud composer environment by myself, and it worked well until a few days ago.

However, for now, when I tried to create a new cloud composer env and to deploy the same DAG that worked well previously, I got a following error message on the Airflow Web UI. And DAG is failed.

```
Broken DAG: [/home/airflow/gcs/dags/xxx.py] Relationships can only be set between Operators; received GoogleCloudStorageToGoogleCloudStorageOperator

```

I couldn't understand why this error occurred even if I used the same code and followed the same procedure to deploy my DAG to the cloud composer.

I appreciate for those who give me any advice to solve this problem.