I’ve seen this type of issue multiple times. If I’m really interested in the item I’ll contact the supplier and often they’re just as flummoxed as me.

Of course then there’s the "other"response as well, where the supplier has no interest in actually shipping outside their own country, but that’s a whole different thing

The worst part is that eBay charges a percentage of the final sale to the seller. It’s possible to lose money by adding one day shipping as a favor to the buyer.