warning in vat-number.php on line 1203

with all wordpress debug flags ON and displayed, I have the following warning showing in the checkout page as soon as I select a EU country (making the VAT field appearing) :

Warning: Illegal offset type in isset or empty in []/woocommerce-eu-vat-compliance-premium/vat-number.php on line 1203

not sure if it’s important or not, but thought I should report it anyway in case you can fix it easily.