Civilization V victory achievements bugged?

So I finally beat almost 20 hour game (yeah, pretty sad right) in civ 5 by eliminating all the other civilizations. For some reason the victory achievements (winning with Japan and winning by annihilating everyone else) didn't unlock. I replayed the final turns from my previous save but it didn't help at all.

It's not a big deal but out of curiosity, has this happened to anyone else? I googled it and there's a similar bug for players with BNW, which I don't have.