Bug when persisting referenced collection

$b1 = new B('first');
$a = new A(array($b1));
$this->dm->persist($a);
$this->dm->flush();
$b2 = new B('second');

$this->dm->refresh($a); // !!!!!!!!

$a->getB()->add($b2);
$this->dm->flush(); // He now adds the initial values there too. Thus, the array first, first and second!

// $this->dm->refresh($a);
$b = $a->getB()->toArray();

$this->assertEquals(2, count($b));

$this->assertEquals(array(
	$b1->getId(), $b2->getId()
), array(
	$b[0]->getId(), $b[1]->getId()
));

namespace Documents\Avatar;

/**
 * @Document(collection="avatars")
 */
class Avatar {

	/**
	 * @Id
	 */
	protected $_id;
	/**
	 * @String(name="na")
	 * @var string
	 */
	protected $_name;
	/**
	 * @int(name="sex")
	 * @var int
	 */
	protected $_sex;
	/**
	 * @EmbedMany(
	 *	targetDocument="Documents\Avatar\AvatarPartTest",
	 *	name="aP"
	 * )
	 * @var array Documents\Avatar\AvatarPartTest
	 */
	protected $_avatarParts;

	/**
	 * Constructor
	 * @param string $name
	 * @param int $sex
	 */
	public function __construct($name, $sex, $avatarParts = null) {
		$this->_name = $name;
		$this->_sex = $sex;
		$this->_avatarParts = $avatarParts;
	}

	/**
	 * @return string
	 */
	public function getId() {
		return $this->_id;
	}

	/**
	 * @return string
	 */
	public function getName() {
		return $this->_name;
	}

	/**
	 * @param string $name
	 */
	public function setName($name) {
		$this->_name = $name;
	}

	/**
	 * @return int
	 */
	public function getSex() {
		return $this->_sex;
	}

	/**
	 * @param int $sex
	 */
	public function setSex($sex) {
		$this->_sex = $sex;
	}

	/**
	 * @return array Documents\Avatar\AvatarPartTest
	 */
	public function getAvatarParts() {
		return $this->_avatarParts;
	}

	/**
	 * @param Documents\Avatar\AvatarPartTest $part
	 */
	public function addAvatarPart($part) {
		$this->_avatarParts[] = $part;
	}

	/**
	 * @param array Documents\Avatar\AvatarPartTest $parts
	 */
	public function setAvatarParts($parts) {
		$this->_avatarParts = $parts;
	}

	/**
	 * @param Documents\Avatar\AvatarPartTest $part
	 */
	public function removeAvatarPart($part) {
		$key = array_search($this->_avatarParts, $part);
		if ($key !== false) {
			unset($this->_avatarParts[$key]);
		}
	}

}

namespace Documents\Avatar;

/**
 * @EmbeddedDocument
 */
class AvatarPartTest {
	/**
	 * @String(name="col")
	 * @var string
	 */
	protected $_color;

	/**
	 * Constructor
	 * @param string $type
	 * @param string $color
	 */
	public function __construct($color = null) {
		$this->_color = $color;
	}

	/**
	 * @return string
	 */
	public function getColor() {
		return $this->_color;
	}

	/**
	 * @param string $color
	 */
	public function setColor($color) {
		$this->_color = $color;
	}

}

$part = new Documents\Avatar\AvatarPartTest();
$avatar = new Documents\Avatar\Avatar('Test', 1, array($part));
$this->dm->persist($avatar);
$this->dm->flush();
$this->dm->refresh($avatar);

$this->dm->getUnitOfWork()->computeChangeSets();
$update = $this->dm->getUnitOfWork()->getDocumentPersister('Documents\Avatar\Avatar')->prepareUpdateData($avatar);
print_r($update);
// print :
Array
(
    [$set] => Array
        (
            [na] => Test
            [sex] => 1
        )
    [$pushAll] => Array
        (
            [aP] => Array
                (
                    [0] => Array
                        (
                        )
                )
        )
)
// That is wrong because it priced the initial values are!

$this->dm->flush();

// First insert
Array
(
    [batchInsert] => 1
    [num] => 1
    [data] => Array
        (
            [0000000061fd6eaa00000000066fdfcd] => Array
                (
                    [na] => Test
                    [sex] => 1
                    [aP] => Array
                        (
                            [0] => Array
                                (
                                )
                        )
                )
        )
    [class] => Documents\Avatar\Avatar
    [db] =>test
    [collection] => avatars
)

// Refresh findOne

// The last flush after refresh
// I have made no updates yet he wants to save the entire document again!

Array
(
    [update] => 1
    [criteria] => Array
        (
            [_id] => MongoId Object
                (
                )
        )
    [newObj] => Array
        (
            [$set] => Array
                (
                    [na] => Test
                    [sex] => 1
                )
        )
    [options] => Array
        (
        )
    [class] => Documents\Avatar\Avatar
    [db] => test
    [collection] => avatars
)

Array
(
    [update] => 1
    [criteria] => Array
        (
            [_id] => MongoId Object
                (
                )
        )
    [newObj] => Array
        (
            [$pushAll] => Array
                (
                    [aP] => Array
                        (
                            [0] => Array
                                (
                                )
                        )
                )
        )
    [options] => Array
        (
        )
    [class] => Documents\Avatar\Avatar
    [db] => test
    [collection] => avatars
)

$this->dm->getUnitOfWork()->computeChangeSets();
$update = $this->dm->getUnitOfWork()->getDocumentPersister('Documents\Avatar\Avatar')->prepareUpdateData($avatar);