I just checked my records and my first noted occurrence of the buyer location problem was back on the 6th of August 2014 but recall earlier enquiries from blocked buyers too but don't want to waste too much time on this; so this problem has been going for a tad longer than is currently being reported.

Also as a side dish; you may notice that ebay has changed all your buyer location preferences to the default setting (your ebay item/s are now in all probability available for sale to Nigeria). Good luck finding where that setting is but will give you a clue (My Account/site preferences/Buyer requirements-show/block buyers who-edit). If you use Turbo Lister a prayer or two to your god figure may help.

I have also noted massive live database merges in progress where entire inventories are down for a day to three days at a time. When they reappear some prices and other details may have been temporaily changed etc.

If you are serious about your selling back up all your files. If you have a massive inventory you will may need to seek the services of a Siberian sweatshop worker (with a Phd in computer science) to help resurrect your catalogue.

Good Luck with it all.