please help me to understand why hibernate search query return as results same records twice. It is a bug or it is my mistake?

@Entity
@Indexed(index="UsersProfileData")
public class UserData implements Serializable {

 private long id;
 private java.lang.String value;

 @Id
 @GeneratedValue(strategy = GenerationType.AUTO)
 @DocumentId
 public long getId() {
 return id;
 }


 public void setId(long id) {
 this.id = id;
 }

 @Field(name="summary", index=org.hibernate.search.annotations.Index.UN_TOKENIZED, store=Store.YES)
 public java.lang.String getValue() {
 return value;
 }


 public void setValue(java.lang.String comment) {
 this.value = comment;
 }
}

String[] values = {"1","2","ab 1","ab 2"}
for(int i=0;i<4;i++){
 UserData u = new UserData ();
 u1.setValue(values);
 em.persist(u);
 }

 FullTextEntityManager fullTextEntityManager =
 org.hibernate.search.jpa.Search.createFullTextEntityManager(em);
 QueryParser parser = new QueryParser("id", new KeywordAnalyzer() );
 org.apache.lucene.search.Query q = parser.parse( "summary:ab*" );
 org.hibernate.search.jpa.FullTextQuery hQuery = fullTextEntityManager.createFullTextQuery(q,UserData.class);

 List result = hQuery.getResultList();
 System.out.println("\n\t*** RESULTS: "+hQuery.getResultSize());