Deprecated Functionality: preg_replace(): Passing null to parameter

I have an issue;

1 exception(s):
Exception #0 (Exception): Deprecated Functionality: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in /var/www/html/vendor/magento/zendframework1/library/Zend/Db/Statement.php on line 222

$_helper = $this->helper('MagentoCatalogHelperOutput');
$_imagehelper = $this->helper('MagentoCatalogHelperImage');
$_product = $block->getProduct();
$specs = $_product->getAttributeText('specifications');
$specs = $specs = $this->helper('MagentoCatalogHelperOutput')->productAttribute($block->getProduct(), $block->getProduct()->getSpecifications(), 'specifications');
$specs = trim( str_replace( array("rn","r", "
" ),"", $specs ) );
$specs = trim( html_entity_decode( $specs ) );