SelectOneMenu does not bring the description of the object in the edit

I'm doing a registration that has a relationship with another, I'm using SelecOneMenu to draw it, when I make a new one it works correctly, but in editing it is not bringing the object of the other class, and when I just save a record and I try to edit it behind the object, but just refresh the page that does not come back, the other text fields, back normally.

public void updateInterface () {

    try {

        Sistema sistema = new Sistema();
        SistemaDao sistemaDao = new SistemaDao();
        sistema = sistemaDao.buscaPorId(idSistema);

        InterfaceDao interfaceDao = new InterfaceDao();
        interfaceSistema.setSistema(sistema);
        interfaceDao.atualizar(interfaceSistema);

        String msg = "Interface " + interfaceSistema.getDescricao() + " Alterada com sucesso";

        FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, msg, msg);
        FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(null, message);

    } catch (RuntimeException e) {
        throw new RuntimeException("Erro ao atualizar a interface no Bean");
    } finally {
        listarInterface();
    }
}

public void selectInterface (ActionEvent event) {

    interfaceSistema = (Interface) evento.getComponent().getAttributes().get("interfaceSelecionado");