Incorrect image reference when launching Dataflow Flex templates

We are using Dataflow Flex Templates and following this guide (https://cloud.google.com/dataflow/docs/guides/templates/using-flex-templates) to stage and launch jobs. This is working in our environment. However, when I SSH onto the Dataflow VM and run docker ps I see it is referencing the a different docker image to the one we speccify in our template (underlined in green):

The template I am launching from is as follows and jobs are created using gcloud beta dataflow flex-template run:

{
"image": "gcr.io/<MY PROJECT ID>/samples/dataflow/streaming-beam-sql:latest",
"metadata": {
    "description": "An Apache Beam streaming pipeline that reads JSON encoded messages from Pub/Sub, uses Beam SQL to transform the message data, and writes the results to a BigQuery",
    "name": "Streaming Beam SQL",
    "parameters": [
        {
            "helpText": "Pub/Sub subscription to read from.",
            "label": "Pub/Sub input subscription.",
            "name": "inputSubscription",
            "regexes": [
                ".*"
            ]
        },
        {
            "helpText": "BigQuery table spec to write to, in the form 'project:dataset.table'.",
            "is_optional": true,
            "label": "BigQuery output table",
            "name": "outputTable",
            "regexes": [
                "[^:]+:[^.]+[.].+"
            ]
        }
    ]
},
"sdkInfo": {
    "language": "JAVA"
}
}

So I would expect the output of docker ps to show gcr.io/<MY PROJECT ID>/samples/dataflow/streaming-beam-sql as the image on Dataflow. When I launch the image from GCR to run on a GCE instance I get the following output when running docker ps:

Should I expect to see the name of the image I have referenced in the Dataflow template on the Dataflow VM? Or have I missed a step somewhere?

Thanks!