Yoast description tag not appearing

Have updated Enfold to latest, WordPress and all plugins updated. In Yoast I have a tag for the description – %%excerpt%%

It’s not appearing in a page, but if I enter a custom description in Yoast page editor, it will appear. Normally not an issue as Google makes it’s own description, but this effects OG/Twitter tags as well.

Why am I posting here instead of Yoast forum? Another site, not based on Enfold, does correctly use the %%excerpt%% template.

I did try the below at the end of my enfold-child functions.php which also didn’t work:

function add_yoast_opengraph_description( $str ) {
	if ( $str == '' ) {
		return get_the_excerpt();
	} else {
		return $str;
	}
}
add_filter( 'wpseo_opengraph_desc', 'add_yoast_opengraph_description' );