@AlsoLoad annotation, used on method causes fatal error

Notice: Undefined index: isCascadePersist in library\Doctrine\ODM\MongoDB\UnitOfWork.php on line 1661

Notice: Undefined index: fieldName in library\Doctrine\ODM\MongoDB\UnitOfWork.php on line 362

Notice: Undefined index: in library\Doctrine\ODM\MongoDB\Mapping\ClassMetadata.php on line 923

Fatal error: Call to a member function getValue() on a non-object in library\Doctrine\ODM\MongoDB\Mapping\ClassMetadata.php on line 923

/** @Document(db="tests", collection="tests") */
class a
{
    /** @Id */
    protected $id;

    /** @String */
    protected $b = 'tmp';

    /** @AlsoLoad("c") */
    function renameC($c) {$this->b = $c;}
    function getId() {return $this->id;}
}

$a = new a();
$dm->persist($a);
$dm->flush();
$dm->getUnitOfWork()->clear();

$a = $dm->loadByID('a', $a->getId());