JPA Hibernate two entities with same name, always saving in the same entity

I have jCombobox where all entidades students are loaded. It happens to have two entities with the same name (two students Rodrigo Silva for example). Both are loaded into combo .

With gravar data in banco , it does not matter which of the two entidades listed with the same name I choose, is always written to id lower (in this case id 1) . What am I doing wrong, how can I resolve this?

public T save(T t) throws Exception {
EntityManager em = getEm();
try {
    em.getTransaction().begin();
    if (t.getId() == null) {
        em.persist(t);

    } else {
        if (em.contains(t)) {
            if (em.find(t.getClass(), t.getId()) == null) {
                throw new Exception("Erro");
            }
        }
        t = em.merge(t);

    }
    em.getTransaction().commit();
} finally {
    em.close();
}
return t;

}

    ocorrencia.setAluno((Aluno) jCAluno.getSelectedItem());
    OcorrenciaDao oc = new OcorrenciaDao();
    oc.save(ocorrencia);

Method that populates combo :

  public void loadComboAluno() {
    AutoCompleteDecorator.decorate(this.jCAluno);
    AlunoDao alunoDao = new AlunoDao();
    List<Aluno> listaAlunos = alunoDao.consultarAlunos();
    for (Aluno set : listaAlunos) {
        jCAluno.addItem(set);
    }
}

Query method:

   public List<Aluno> consultarAlunos() {
    EntityManager em = getEm();
    List<Aluno> listaAlunos;
    try {
        Query q = em.createNamedQuery("Aluno.findAll");
        listaAlunos = q.getResultList();
    } catch (Exception e) {
        listaAlunos = new ArrayList<>();

    } finally {
        em.close();

    }
    return listaAlunos;

}

Student Class:

    @Entity
@DynamicUpdate(value=true)
@NamedQueries({
    @NamedQuery(name = "Aluno.findAll", query = "SELECT c FROM Aluno c"),
    @NamedQuery(name = "Aluno.findByAlunoId", query = "SELECT c FROM Aluno c WHERE c.id = :id"),
    @NamedQuery(name = "Aluno.findByAlunoNome", query = "SELECT c FROM Aluno c WHERE c.nome = :nome")})
public class Aluno implements EntidadeBase, Serializable {

    @Id

    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "idAluno")
    private Integer id;
    @Column(name = "nomeAluno")
    private String nome;