ASP.NET Web API duplicate endpoints

In my ASP.NET web application I have two types of controllers:

1) Web API controllers: 'System.Web.Http.ApiController'

2) Odata controllers: 'Microsoft.AspNet.OData.ODataController'

I have a problem with PUT and DELETE methods- I'm creating these methods only in ApiController but when I run the application I see these endpoints also as Odata endpoints. The delete method is decorated by [HttpDelete] attribute:

[HttpDelete]
[Route("{id:int}")]
public IHttpActionResult RemoveEmployee(int id)
{
    return Ok();
}

In the OData controller class, I'm creating only the Get method.

In Swagger it looks like this - DELETE endpoint is duplicated:

Swagger

ODataController class:

    [ApiVersion( "2.0" )]
    [ODataRoutePrefix( "Employee" )]
    public class EmployeeController : ODataController
    {
        [HttpGet]
        [ODataRoute]
        [ResponseType( typeof( ODataValue<IEnumerable<Employee>> ) )]
        [EnableQuery( MaxTop = 100, AllowedQueryOptions = Select | Top | Skip | Count )]
        public IQueryable<Employee> Get()
        {
            var empl = new[]
{
                new Employee(){ EmplId = 11, Name = "John Smith", Age = 50 },
                new Employee(){ EmplId = 21, Name = "Bob Smith", Age = 70}
                        };

            return empl.AsQueryable();
        }
    }

ApiController class:

    [ApiVersion( "2.0" )]
    [RoutePrefix( "api/Employee" )]
    public class EmployeeController : ApiController
    {

        [HttpGet]
        [Route( "" )]
        public string Get()
        {
            var empl = new[]
{
                new Employee(){ EmplId = 11, Name = "John Smith", Age = 50 },
                new Employee(){ EmplId = 21, Name = "Bob Smith", Age = 70}
                        };

            string ret = string.Empty;

            foreach ( var item in empl )
            {
                ret += $"{item.EmplId}, {item.Name}, {item.Age.ToString()}";
            }

            return ret;
        }

        [HttpPost]
        [Route("")]
        public IHttpActionResult InsertEmployee(Employee employee)
        {
            return Ok();
        }

        [HttpDelete]
        [Route("{id:int}")]
        public IHttpActionResult RemoveEmployee([FromUri] int id)
        {
            return Ok();
        }

    }