Fatal error: Call to a member function get_meta() on bool

Got this error message and info displayed below when attempting to print a PDF Credit Note. Regular PDF Invoices and Packing Slips work normally.

Fatal error: Call to a member function get_meta() on bool
#0 /var/www/html/wp-content/plugins/woocommerce-pdf-ips-pro/includes/wcpdf-pro-functions.php(503): WPO\WC\PDF_Invoices\Compatibility\Data::get_meta()
#1 /var/www/html/wp-content/plugins/woocommerce-pdf-ips-pro/woocommerce-pdf-ips-pro.php(217): WooCommerce_PDF_IPS_Pro_Functions->get_number()
#2 /var/www/html/wp-content/plugins/woocommerce-pdf-ips-pro/includes/wcpdf-pro-functions.php(197): WooCommerce_PDF_IPS_Pro->get_number()
#3 /var/www/html/wp-includes/class-wp-hook.php(287): WooCommerce_PDF_IPS_Pro_Functions->build_filename()
#4 /var/www/html/wp-includes/plugin.php(206): WP_Hook->apply_filters()
#5 /var/www/html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(752): apply_filters()
#6 /var/www/html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/class-wcpdf-bulk-document.php(120): WPO\WC\PDF_Invoices\Documents\Order_Document->get_filename()
#7 /var/www/html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/class-wcpdf-bulk-document.php(102): WPO\WC\PDF_Invoices\Documents\Bulk_Document->get_filename()
#8 /var/www/html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-main.php(340): WPO\WC\PDF_Invoices\Documents\Bulk_Document->output_pdf()
#9 /var/www/html/wp-includes/class-wp-hook.php(287): WPO\WC\PDF_Invoices\Main->generate_pdf_ajax()
#10 /var/www/html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters()
#11 /var/www/html/wp-includes/plugin.php(478): WP_Hook->do_action()
#12 /var/www/html/wp-admin/admin-ajax.php(175): do_action()
#13 {main}