[PHP]Warning information will appear using cubrid_unbuffered_query() method when table just has one record

$conn = cubrid_connect("localhost", 33113, "demodb","dba","");
cubrid_execute($conn, 'DROP TABLE IF EXISTS unbuffered_tb');
cubrid_execute($conn,"CREATE TABLE unbuffered_tb(id int, name varchar(10))");
cubrid_execute($conn,"insert into unbuffered_tb values(1,'name1')");
$res=cubrid_unbuffered_query("SELECT * FROM unbuffered_tb ; ", $conn);
if (!$res) {
    printf("[006] [%d] %s\n", cubrid_errno($conn), cubrid_error($conn));
}else{
    var_dump(cubrid_fetch_assoc($res));
}
cubrid_free_result($res);
cubrid_close($conn);

PHP Warning:  Error: CAS, -1006, Server handle not found in /home/php/phpTestcases/_11/unbuffered_test1.phpt on line 11
array(2) {
  ["id"]=>
  string(1) "1"
  ["name"]=>
  string(5) "name1"