Lookup Activity in Azure Data Factory is not reading JSON file correctly and appending some additional data

I am trying to read JSON file stored in Azure Blob container and use the output in setting a variable but I am getting some addition data apart from main data. My JSON input is

{
  "resourceType": "cust",
  "gender": "U",
  "birthdate": "1890-07-31",
  "identifier": [
    {
      "system": "https://test.com",
      "value": "test"
    }
  ],
  "name": [
    {
      "use": "official",
      "family": "Test",
      "given": [
        "test"
      ],
      "prefix": [
        "Mr"
      ]
    }
  ],
  "telecom": [
    {
      "system": "phone",
      "value": "00000",
      "use": "home"
    }
  ]
}

The output of lookup activity is:

{
    "count": 1,
    "value": [
        {
            "JSON_F52E2B61-18A1-11d1-B105": "[{\"resourceType\":\"cust\",\"identifier\":[{\test.com",\"value\":\"test\"}],\"name\":[{\"use\":\"official\",\"family\":\"Test\",\"given\":\"[ Test ]\",\"prefix\":\"[ ]\"}],\"telecom\":[{\"system\":\"phone\",\"value\":\"00000\",\"use\":\"home\"}],\"gender\":\"unknown\",\"birthDate\":\"1890-07-12T00:00:00\"}]"
        }
    ]
}

Now I don't understand why

1. in value JSON_F52E2B61-18A1-11d1-B105 is present?
2. so many \ are there, while it is not present in actual JSON?