Just noticed this while starting a custom game with RFC Marathon:

http://forums.civfanatics.com/attachment.php?attachmentid=256340&stc=1&d=1277466294

Why do we have two Russias?

It's not a bug.

Those are not Russias, those are two Minor Civs (independents). It's exactly the same in plain RFC - you're just not supposed to use "Custom Game/Scenario" with RFC, which is why it's normally disabled.

Also, please use the main RFCMarathon thread (http://forums.civfanatics.com/showthread.php?t=354241) to report actual bugs, there's no reason to create a new thread to do it.