Quote::transformToExternalValue

protected function transformToExternalValue(string $entityFieldName, $fieldValue, int $valuesType = Values::ALL)
{
	$value = parent::transformToExternalValue($entityFieldName, $fieldValue, $valuesType);

	$commonFieldName = $this->getCommonFieldNameByMap($entityFieldName);
	if($commonFieldName === static::FIELD_NAME_STORAGE_ELEMENTS && is_array($value))
	{
		return serialize($value);
	}

	return $value;
}