Objeto vem nulo - JSF e Primefaces

<p:dataTable id="tabela"
                                 var="instituicoes"
                                 value="#{instituicaoMB.exibirTodasInstituicoes()}"
                                 emptyMessage="Nenhum registro encontrado"
                                 selectionMode="single"
                                 selection="#{instituicaoMB.instituicaoBeanAux}"
                                 rowKey="#{instituicoes.idInstituicao}"
                                 paginator="true"
                                 rows="6"
                                 paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} 
                                 {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}">
                        <p:ajax event="rowSelect" listener="#{instituicaoMB.linhaSelecionada}" />
//restante das colunas da tabela

@ManagedBean
@RequestScoped
public class InstituicaoMB {

private InstituicaoBean instituicaoBeanAux;

 public InstituicaoMB() {
this.instituicaoBeanAux = null;
}

public void linhaSelecionada(SelectEvent event) {
        setInstituicaoBeanAux((InstituicaoBean) event.getObject());
        System.out.println("Inst: " + this.getInstituicaoBeanAux());
    }
}

@FacesConverter(value = "conversorInstituicao", forClass = InstituicaoBean.class)
public class ConversorInstituicaoBean implements Converter {

    @Override
    public Object getAsObject(FacesContext fc, UIComponent uic, String valor) {
        Integer idInstituicao;
        
        if(valor == null || "".equals(valor)) {
            return null;
        }
        
        String[] id = valor.split(" ");
        idInstituicao = Integer.parseInt(id[1]);
               
        
        if(id[1] != null) {
            InstituicaoDAOImpl instituicaoDAOImpl = new InstituicaoDAOImpl();
            return instituicaoDAOImpl.buscarInstituicaoPorId(idInstituicao);
        }
        return null;
    }

    @Override
    public String getAsString(FacesContext fc, UIComponent uic, Object object) {
        if (object != null && object instanceof InstituicaoBean) {
            return ((InstituicaoBean)object).toString();
        }
        return null;
    }
    
}