So wait, just to be sure: is it something that affects players who have moved countries, countries with different currencies, or regions?

Because I might run into the same problem in 3 months if it's the first case...

For EU Fanfest I was one of the finalists and they ask you to confirm your address in case you win a physical prize, very silly that I was able to change the address itself but not the country : o )
(good thing I didn't win anything, but I wondered if they would figure out that the capital was not matching the country and they'd have to ship it to the right one...)