Use a Service-Account for Pub/Sub policy not working in Apigee Emulator

[jallen-fni]

going through the documentation for setting up the Apigee Emulator docker container to mount the keys directory, and referencing the Service account properly in the deployments.json all seems to be setup correctly. But when trying to use a PublishMessage policy, we receive this error:

{
    "fault": {
        "faultstring": "Encountered the following exception while publishing message: [com.google.api.gax.rpc.UnavailableException: io.grpc.StatusRuntimeException: UNAVAILABLE: Credentials failed to obtain metadata].",
        "detail": {
            "errorcode": "steps.publishmessage.ExecutionError"
        }
    }
}

From what i can tell our service account has all the correct permissions. Does this just not work yet for the PublishMessage policy?

Have tested with 1.9.4 and 1.11.1 versions of the emulator