The parameter 'misc::workflow' is invalid

When using the Model Derivative API's POST Job endpoint and trying to set the misc >> workflow parameter

{
    "input": {
        "urn": "{{Urn}}",
        "compressedUrn": true,
        "rootFilename": "{{RootFileName}}"
    },
    "output": {
        "destination": {
            "region": "us"
        },
        "formats": [
        {
            "type": "svf",
            "views": ["3d", "2d"]
        }]
    },
    "misc": {
    	"workflow": "my_workflow_id"
    }
}

you might get the following reply:

{
    "diagnostic": "The parameter 'misc::workflow' is invalid."
}

The most likely cause is that you are using some invalid characters in the workflow value - like underscores "_"