Another Critical Error in Stand Alone Plugin

I get a critical error in the admin while editing posts/pages since upgrading to WP 5.4, and upgrading ACF 5.8.9, very similar to this topic, however I was asked to open up a new topic, so here you go.

Running 1.0.3 of the standalone plugin Schema Markup Rich Snippets.
This is the error I got (the asterisks in nlboom-*** I put there for security purposes):

Stack trace: 
#0 /var/www/nlboom-***/wordpress/current/wp-includes/class-wp-hook.php(287): RANKMATH_SCHEMA\Admin\Metabox\Metabox->enqueue('post.php') 
#1 /var/www/nlboom-***/wordpress/current/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array) 
#2 /var/www/nlboom-***/wordpress/current/wp-includes/plugin.php(478): WP_Hook->do_action(Array) 
#3 /var/www/nlboom-***/wordpress/current/wp-admin/admin-header.php(104): do_action('admin_enqueue_s...', 'post.php') 
#4 /var/www/nlboom-***/wordpress/current/wp-admin/edit-form-advanced.php(419): require_once('/var/www/nlboom...') 
#5 /var/www/nlboom-***/wordpress/current/wp-admin/post.php(206): require('/var/www/nlboom...') 
#6 {main} 
thrown