Retrieved changed DOM HTML - missing <script type="json+ld"> tags

[An147]

Hi! I'm working on a WordPress project where I need to replace all alt attributes for tags if there is no alt, or alt attribute is empty. So I have this filter function: ` function replace_empty_alt_tags($content){ global $post;

$dom = new Dom;
$dom->loadStr($content);
$imageNodes = $dom->find('img');

foreach ($imageNodes as $node){
	if ( empty($node->getAttribute( 'alt' )) ){
		$node->setAttribute( "alt", get_the_title( $post->ID )." | CANNOVIA" );
	}
}

$content = $dom->__toString();
return $content;

} `

It works well, but it removes Schema markup made with LD-JSON tags. So it's missing it. Maybe I retrieve DOM HTML content in a wrong way (at the end)? Or this is really a bug?