Duplicated Records Being Returned by Web API Method

I have created what I thought to be a simple controller selecting on a database view. However, the first record is returned multiple times in the JSON result. For example, when filtering using Odata, 7 different records are expected however, 7 of the same record are being returned.

Here is the controller code:

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using System.Web.Http.Description;
using MyAPI.WebAPI.Models;
using System.Web.OData;
using System.Security.Principal;
using System.Web;

namespace MyAPI.WebAPI.Controllers
{
    public class MyViewController : ApiController
    {
        private MyEntities db = new MyEntities();

        // GET
        [EnableQuery] // Enables OData query integration
        public IHttpActionResult GetMetrics()
        {
            return Ok(db.ViewResults.AsQueryable());
        }
    }
}

When using a breakpoint on the return statement, I can see where all 4000 results are being returned in the query and the OData seems to be filtering only the 7 records I need but when it is sent via JSON string it is duplicated.

Has anyone experienced anything like this?