This had been freaking me out for months! But I think I finally figured it out in my case. I had used Picasa to upload the pics years ago. In Picasa, I had ent

This had been freaking me out for months! But I think I finally figured it out in my case. I had used Picasa to upload the pics years ago. In Picasa, I had entered a caption with enough detail for Facebook to guess the location. The caption had never been uploaded (i.e. set as the photo's caption on Facebook), but I'm guessing they did somehow capture that info on upload.