Preventing Global Meta Description Overwrite

Hello,

Thank you for contacting Rank Math support.

You will have to add the following filter to use the global description when an excerpt is present:

add_action( 'rank_math/frontend/description', function( $description ) {
	global $post;
	$desc = RankMath\Post::get_meta( 'description', $post->ID );

	if ( is_single()) {
		 $desc = RankMath\Helper::get_settings( "titles.pt_{$post->post_type}_description" );
		 if ( $desc ) {
		 	return RankMath\Helper::replace_vars( $desc, $post );
		 }
	}
	
	return $description;
	
});

Here is how to add a filter to your site: https://rankmath.com/kb/wordpress-hooks-actions-filters/

Hope that helps and please do not hesitate to let us know if you need our assistance with anything else.