It’s happening with my site too – which is annoying since when I receive the payments I get charged a paypal fee, have to figure out who the payment was supposed to go to and manually transfer the payment to them (who presumably also gets charged a paypal fee for accepting the shipping they should have been sent).
So it’s costing not only time, but money each time in pp fees.
It’s happening on both old products and new ones added after the update. We’re using vendor shipping (country table rate) and everything is paid to vendors (all shipping and all commissions)