Why doesn't the web API controller action override the deserialization of the child properties of the child properties?

I am sending a json payload in a PUT request for a web API controller action. The action in question has a signature that looks like this:

public IHttpActionResult Post([FromBody]SaveThingRequest request)

      

        
        
        
      

    

SaveThingRequest looks something like this:

public class SaveThingRequest
{
    public List<ElementInfo> Elements { get; set; }

    public class ElementInfo
    {
        public List<ElementSettingInfo> Settings { get; set; }

        public class ElementSettingInfo
        {
            public string Name { get; set; }
            public string Value { get; set; }
        }
    }
}

      

        
        
        
      

    

I am sending json to the body of the request containing the Customized Items. I confirmed this by doing manual deserialization in a controller action and confirming that the JSON has a structure that looks something like this:

{
    Elements: [
        {
            Settings: [
                {
                    Name: 'Name 1',
                    Value: 'Value 1'
                },
                {
                    Name: 'Name 2',
                    Value: 'Value 2'
                }
            ]
        },
        {
            Settings: [
                {
                    Name: 'Name 1',
                    Value: 'Value 1'
                },
                {
                    Name: 'Name 2',
                    Value: 'Value 2'
                }
            ]
        }
    ]
}

      

        
        
        
      

    

However, when .NET deserializes the payload and creates the SaveThingRequest, my items get populated, but they all have a null Settings property. I don't know how else to fix this. Anyone have any thoughts on what might be going on here?