Schema Not Picking Meta Description from Yoast SEO data

By default, the Schema plugin will grab the first paragraph and use part of it as a description. However, you can override that to use any other source for the description (example: Yoast SEO description post meta value)

Here is a working example code that you can use:

add_filter( 'schema_output', 'schema_wp_override_description_yoast_seo_12345' );
/*
*	Override Schema description value with Yoast SEO description
*/
function schema_wp_override_description_yoast_seo_12345( $schema_output ) {
	
	// get description value from Yoast SEO post meta
	$desc = get_post_meta( get_the_ID(), '_yoast_wpseo_metadesc', true);
	
	// override the value in schema output
	$schema_output["description"] = $desc;
	
	// return our schema array
	return $schema_output;
}

P.S. This code can be added to your Theme’s functions.php file. Once you add the code, go to Schema > Types > edit any of the types you have and save it (this will flush the saved schema markups so changes will take effect)

I hope this helps.