I decided to try a game of RUS now the new patch has come out. I'm playing the DNO scenario solo as the Reds against the AI. I accepted the German ultimatum to start the game, and crushed the Southern Whites. Now, I have turned on the Transcaucasus. Only problem is, our forces won't fight. The Transcaucasus armies are marching through my lines on their way to various points in the interior of Red territory, while my boys march unopposed to their various objectives. I don't appear to be getting any MC in the regions I have entered either. When I hover over the Transcaucaus armies, they are reported as being "German, cordial relations". I'm betting that somehow I have not actually gone to war with them.
So much for the "one enemy at a time" strategy.
I can send a save game to anybody who would like one, please message me your email address.