Comportamento estranho hibernate

public class Pessoa extends AbstractBean {

	private Integer id;

	private String nome;

	private Set<ItemPessoa> itens;

        /*GETTERS and SETTERS*/
}

public class ItemPessoa extends AbstractBean {

	private Integer id;
       
        private String descricao;
	
	private Pessoa pessoa;

    /*GETTERS and SETTERS*/

}

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping auto-import="true">
	<class name="br.com.ssd.bean.Pessoa" schema="cad" table="pessoa" dynamic-update="true">
		<id name="id" type="integer">
			<generator class="sequence">
				<param name="sequence">cad.pessoa_id_seq</param>
			</generator>
		</id>
		<property name="nome" type="string" column="numero" />
		
		<set name="itens" table="cad.item_pessoa" cascade="all" outer-join="true" fetch="subselect">
			<key column="id_pessoa" />
			<one-to-many class="br.com.ssd.bean.ItemPessoa" />
		</set>
	</class>
</hibernate-mapping>

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping auto-import="true">
	<class name="br.com.ssd.bean.ItemPessoa" schema="cad" table="item_pessoa" dynamic-update="true">
		<id name="id" type="integer">
			<generator class="sequence">
				<param name="sequence">cad.item_pessoa_id_seq</param>
			</generator>
		</id>
		<property name="descricao" type="string" column="descricao" />		
		<many-to-one name="pessoa" class="br.com.ssd.bean.Pessoa" column="id_pessoa" cascade="none" outer-join="false" />
	</class>
</hibernate-mapping>