Type date_range formatting v6.8 vs v7.12

Hello,
I am upgrading from ES 6.8 to ES 7.12.1 and I have a dynamic template like:

"dynamic_templates": [
        {
          "ecom_data": {
            "mapping": {
              "type": "date_range",
              "format": "yyyy-MM-dd'T'HH:mm:ssZ"
            },
            "match_mapping_type": "object",
            "path_match": "ecom_data.*"
          }
        }
      ]

However when I try to index in ES 7.12.1 I get this error:

"type" : "mapper_parsing_exception",
          "reason" : "failed to parse field [ecom_data.free_value] of type [date_range] in document with id 'ecom:data:0NLAD0hvAUqKejb'. Preview of field's value: '2019-12-11T00:01:00Z'",
          "caused_by" : {
            "type" : "parse_exception",
            "reason" : "failed to parse date field [2019-12-11T00:01:00Z] with format ['yyyy-MM-ddTHH:mm:ssZ']: [failed to parse date field [2019-12-11T00:01:00Z] with format ['yyyy-MM-ddTHH:mm:ssZ']]",
            "caused_by" : {
              "type" : "illegal_argument_exception",
              "reason" : "failed to parse date field [2019-12-11T00:01:00Z] with format ['yyyy-MM-ddTHH:mm:ssZ']",
              "caused_by" : {
                "type" : "date_time_parse_exception",
                "reason" : "date_time_parse_exception: Text '2019-12-11T00:01:00Z' could not be parsed at index

I have tried different combinations of "format": "yyyy-MM-dd'T'HH:mm:ssZ" like "format": "'yyyy-MM-ddTHH:mm:ssZ'" but all fail. What has changed with data_range between ES6 and ES7? Thanks!