Automatic and manual splitting not working

Hey! We use the inclusive mode and selected two products. Unfortunately the split does not work. When doing it manually it keeps spinning and then I get these errors.

Notice: Function wc_get_order was called incorrectly. wc_get_order should not be called before post types are registered (woocommerce_after_register_post_type action) Backtrace: require_once('wp-admin/admin.php'), require_once('wp-load.php'), require_once('wp-config.php'), require_once('wp-settings.php'), do_action('plugins_loaded'), WP_Hook->do_action, WP_Hook->apply_filters, wc_os_order_splitter->splitCheck, wc_os_get_order_meta, wc_get_order, wc_doing_it_wrong Please see Debugging in WordPress for more information. (This message was added in version 2.5.) in /home/customer/www/WEBSITE.com/public_html/wp-includes/functions.php on line 6078

Warning: array_key_exists() expects parameter 2 to be array, string given in /home/customer/www/WEBSITE.com/public_html/wp-content/plugins/woo-order-splitter/inc/functions.php on line 244