Crash récurrent

Hello

We have almost every day this fatal error from the plugin :

Une erreur de type E_ERROR a été causée dans la ligne 661 du fichier /home/u816376153/domains/adopteunbrasseur.fr/public_html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-admin.php. Message d’erreur : Uncaught Error: Call to a member function get_id() on null in /home/u816376153/domains/adopteunbrasseur.fr/public_html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-admin.php:661
Stack trace:
# 0 /home/u816376153/domains/adopteunbrasseur.fr/public_html/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-admin.php(600): WPO\WC\PDF_Invoices\Admin->output_number_date_edit_fields()
# 1 /home/u816376153/domains/adopteunbrasseur.fr/public_html/wp-admin/includes/template.php(1443): WPO\WC\PDF_Invoices\Admin->data_input_box_content()
# 2 /home/u816376153/domains/adopteunbrasseur.fr/public_html/wp-admin/edit-form-advanced.php(688): do_meta_boxes()
# 3 /home/u816376153/domains/adopteunbrasseur.fr/public_html/wp-admin/post.php(206): require('/home/u81637615...')
# 4 {main}
thrown

What can we do to fix that ?

Thank you in advance

The page I need help with: [log in to see the link]