TextContent and formatting date fields

[OwainCatton]

I am trying to customizing a popupTemplate for a FeatureLayer, but when I try and use a date field in the TextContent which has had its FieldInfo format set it is outputted as a long integer which I assume is seconds.

let joinedFields =  new FieldsContent({
        fieldInfos: [
            {
                fieldName: "A_Date",
                format: {
                    dateFormat: "day-short-month-year"
                }
            }
        ]
    });

    let joinedtext = new TextContent({
        text: "<h4>Meter Readings</h4>"+
              "<table class=\"table-condensed table-striped gw-table-meters\">"+
              "<thead>"+
              "<tr><th scope=\"col\">Date</th><th scope=\"col\">Reading</th><th scope=\"col\">Usage</th><th scope=\"col\">Code</th><th scope=\"col\">Days</th><th scope=\"col\">Avg</th></tr></thead>"+
              "<tr><td>{A_Date}</td><td>{A_Reading}</td><td>{A_Usage}</td><td>{A_Code}</td><td>{A_No_of_Da}</td><td>{A_UseADay}</td></tr>"+
              "<tr><td>{B_Date}</td><td>{B_Reading}</td><td>{B_Usage}</td><td>{B_Code}</td><td>{B_No_of_Da}</td><td>{B_UseADay}</td></tr>"+
              "<tr><td>{C_Date}</td><td>{C_Reading}</td><td>{C_Usage}</td><td>{C_Code}</td><td>{C_No_of_Da}</td><td>{C_UseADay}</td></tr>"+
              "<tr><td>{D_Date}</td><td>{D_Reading}</td><td>{D_Usage}</td><td>{D_Code}</td><td>{D_No_of_Da}</td><td>{D_UseADay}</td></tr>"+
              "<tbody>"+
              "</tbody></table>"
    });

    let joinedPopup = new PopupTemplate({
        title: "Joined: {Supply_No}",
        outFields: ["*"],
        content: [joinedFields,joinedtext]
    });‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

As you can see from the screen shot above the A_Date is not formatted correctly in the TextContent but is in the FieldsContent.