This achievement is still obtainable, but I believe it is glitchy and this solution may not work for everyone. I got this on my Xbox 360, and apparently it doesn't work for backwards compatibility but I just played a quick online match then went to theater -> Temporary History -> File Options and saved it -> Local Files -> Multiplayer -> Forge World -> File Options and Uploaded to file share. It took a couple of attempts to upload it to file share before I got a successful transfer but once I did, it popped right away!
Hope it works out!