Started a game after maintenance and my entire team and I agreed that all of the minions were blue. I uploaded a picture on imgur, so check that out. As you can see, all of the minions are blue and the only way of identifying a friendly vs an enemy minion is by looking at the hp bar.
To Recreate: Be on the red side of a game.
Solution (From Minecracked): Options->Game->Uncheck "Use Relative Team colors"