Squarespace Postcodes

Hi,

Not sure where this problem sits, but we recently missed an order that wasn't imported into Shipstation.

The customer had somehow managed to enter a delivery address without a postcode. Speaking to support if the order doesn't have a postcode it ignores it. Whereas if they put "jkdshgkh" it would but flag the address as incomplete. Is there a reason that if it's blank it doesn't import it and flag it as incomplete?

Thanks