Make the BeyondWords column sortable in admin

I want to make the BeyondWords column sortable in admin posts page, but so far I haven’t been able to. I have added the code below to functions.php, the column seems to have become sortable, but the sorting doesn’t work correctly – posts with audio always show up mixed with those without. How can this be solved?

add_filter( 'manage_edit-post_sortable_columns', function( $columns ) {

	// make column 'beyondwords' sortable
	$columns['beyondwords'] = 'beyondwords';

	return $columns;
} );