Code First generating a foreign key

I have the following classes

public class ControleDeVisitas
{
    public virtual ICollection<TipoDeSistemas> TipoDeSistemas { get; set; }
}

 public class TipoDeSistemas
 {
    public Guid TipoDeSistemasId { get; set; }
    public string Descricao { get; set; }
    public DateTime DataCadastro { get; set; }
 }

In this way, in the table, TIPO DE SISTEMAS, a key ControleDeVisitaId

This is the method I use to add a TipoDeSistema to Controle

    public ControleDeVisitasViewModel Adicionar(ControleDeVisitasViewModel controleDeVisitasViewModel, List<Guid> sistemasComerciais)
     {
var controle = Mapper.Map<ControleDeVisitas>(controleDeVisitasViewModel);
       foreach (var sistema in sistemasComerciais)
      {
        var ts = _tipoDeSistemaRepositorio.BuscarPorId(sistema);
        controle.TipoDeSistemas.Add(ts);
      }
     _controleDeVisitaRepositorio.Adicionar(controle);
     }

And this is how thebelah is getting TipoDeSistemas

I deleted some data, but the truth is that it is duplicating the same information, like, if I choose the system A, B and C. (Both must already be registered).

It creates a new system Type A, B and C in the same table. and put the control key.

Does anyone know to tell me because he is creating this key in Table TipoDeSistema?

So is my config:

 public ControleDeVisitasConfig()
    {
            ToTable("ControleDeVisitas");
            HasKey(c => c.ControleDeVisitasId);
            HasMany(c => c.TipoDeSistemas);
    }