gcloud sql users create with cloud_iam_group

gistfile1.txt

 ~ % gcloud sql users create group@domain.com --instance=main-instance-3c1f9de9 --type=cloud_iam_group --verbosity=debug
DEBUG: Running [gcloud.sql.users.create] with arguments: [--instance: "main-instance-3c1f9de9", --type: "cloud_iam_group", --verbosity: "debug", USERNAME: "group@domain.com"]
DEBUG: Making request: POST https://oauth2.googleapis.com/token
DEBUG: Starting new HTTPS connection (1): oauth2.googleapis.com:443
DEBUG: https://oauth2.googleapis.com:443 "POST /token HTTP/1.1" 200 None
DEBUG: Starting new HTTPS connection (1): sqladmin.googleapis.com:443
DEBUG: https://sqladmin.googleapis.com:443 "POST /sql/v1beta4/projects/<project-id>/instances/main-instance-3c1f9de9/users?alt=json HTTP/1.1" 200 None
Creating Cloud SQL user...⠛DEBUG: Starting new HTTPS connection (1): sqladmin.googleapis.com:443
DEBUG: https://sqladmin.googleapis.com:443 "GET /sql/v1beta4/projects/<project-id>/operations/6a070e1d-b4b6-48fb-9f64-664a00000024?alt=json HTTP/1.1" 200 None
Creating Cloud SQL user...failed.
DEBUG: (gcloud.sql.users.create) [INTERNAL_ERROR]
Traceback (most recent call last):
  File "/Users/localuser/Applications/google-cloud-sdk/lib/googlecloudsdk/calliope/cli.py", line 987, in Execute
    resources = calliope_command.Run(cli=self, args=args)
  File "/Users/localuser/Applications/google-cloud-sdk/lib/googlecloudsdk/calliope/backend.py", line 807, in Run
    resources = command_instance.Run(args)
  File "/Users/localuser/Applications/google-cloud-sdk/lib/surface/sql/users/create.py", line 129, in Run
    return RunBaseCreateCommand(args)
  File "/Users/localuser/Applications/google-cloud-sdk/lib/surface/sql/users/create.py", line 104, in RunBaseCreateCommand
    operations.OperationsV1Beta4.WaitForOperation(sql_client, operation_ref,
  File "/Users/localuser/Applications/google-cloud-sdk/lib/googlecloudsdk/api_lib/sql/operations.py", line 97, in WaitForOperation
    return retryer.RetryOnResult(
  File "/Users/localuser/Applications/google-cloud-sdk/lib/googlecloudsdk/core/util/retry.py", line 249, in RetryOnResult
    if not should_retry(result, state):
  File "/Users/localuser/Applications/google-cloud-sdk/lib/googlecloudsdk/api_lib/sql/operations.py", line 80, in ShouldRetryFunc
    raise result
googlecloudsdk.api_lib.sql.exceptions.OperationError: [INTERNAL_ERROR]
ERROR: (gcloud.sql.users.create) [INTERNAL_ERROR]