Repeats the custom attribute

when I use this method to get custom attributes

$objectManager = MagentoFrameworkAppObjectManager::getInstance();
$_product = $objectManager->get('MagentoCatalogModelProduct')->load($block->getItem()->getProductId());
echo '' . $_product->getData('custom_attribute'). '';

in this place design/fronend/theme/Magento_Checkou/templates/cart/item/default.phtml (page checkout/cart, list products), this method repeat custom attribute. When a product has no attribute, it takes from the previous product.