I'm unsure if the schema that you are parsing above is the correct one though (I might be misunderstanding). If I edit your json to the following:

{
  "extendedinformation":[
      {
          "name": "CHANNEL",
          "value": "[{\"id\":\"DUMMYID1\",\"name\":\"DUMMYCHANNEL1\",\"role\":\"DUMMYROLE1\"}]"
      }
  ]
}

Then I can't even get the `parse_json()` function to parse (although the above is valid json).