I am facing very strange problem where the response of my .net core web api ommits the nested array beyond level one.

So I am trying to return this structure from my api

var response = new FormHierarchyResponse()
{
    FormTitle = "First level",
    Children = new List<FormDefinitionResponse>(){
        new FormHierarchyResponse() {
            FormTitle="Second Level",
            Children={ 
                new FormDefinitionResponse() {
                FormTitle="Third Level"
                }
            }
        }
    }
};

This is a hierarichal structure which has root, first and second level but I never receive any level beyond second level. So this is the output I receive

{
  "children": [
    {
      "formDefinitionId": 0,
      "formTitle": "Second Level",
      "parentFormDefinitionId": null,
      "warnings": 0,
      "errors": 0,
      "commentsCount": 0
    }
  ],
  "formDefinitionId": 0,
  "formTitle": "First level",
  "parentFormDefinitionId": null,
  "warnings": 0,
  "errors": 0,
  "commentsCount": 0
}

You can see the Second Level children does not even have the children property.

Any idea what is going on here?