GAE Managed VM with automatic scaling and resource

问题:

I'm experiencing the following error intermittently while deploying a java application to appengine using managed VMs with explicit resource configuration:

Deployment failed: https://www.googleapis.com/autoscaler/v1beta2/projects/managedvm409example/zones/us-central1-f/autoscalers?alt=json returned "Autoscaler resource with this name already exists in this zone or there exists an Autoscaler controlling the given target."> Deployed Version: 1.385892435190233331

Here's the configuration I'm using:

<?xml version="1.0" encoding="utf-8"?>
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
    <application>managedvm409example</application>
    <version>1</version>

    <threadsafe>true</threadsafe>

    <precompilation-enabled>false</precompilation-enabled>

    <vm>true</vm>

    <automatic-scaling>
        <min-num-instances>2</min-num-instances>
        <max-num-instances>10</max-num-instances>
        <cool-down-period-sec>90</cool-down-period-sec>
    </automatic-scaling>

    <resources>
        <cpu>1</cpu>
        <memory-gb>4</memory-gb>
        <disk-size-gb>10</disk-size-gb>
    </resources>

    <system-properties>
        <property name="java.util.logging.config.file" value="WEB-INF/logging.properties" />
    </system-properties>
</appengine-web-app>

The problem seems to go away if the automatic-scaling configuration element is removed, but there doesn't seem to be anything exotic in there. Anyone have any ideas on what might be going on?

EDIT: The situation doesn't really change with automatic-scaling removed, apparently, it's just intermittent.