The JSON template created by a pyplate with nested joins.

template.json

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "demonstration of an error with nested joins.",
  "Resources": {
    "Value": {
      "Fn::Join": [
        "",
        [
          "site_url: ",
          [
            {
              "Fn::Join": [
                ".",
                [
                  {
                    "Ref": "AWS::StackName"
                  },
                  "mmstacks.net"
                ]
              ]
            }
          ]
        ]
      ]
    }
  }
}