So I know there is a bug that you may face the same enemy you fight in last rift battle, but that is for only one node. What I hit here is the whole base, i.e. ALL nodes in it are the same as last fight. This happened at Dec 23 GMT8 on my iPad 2018. I lost one rift battle and started another, and when I go to opponent's base, I found that all the defenders' setup are just the same as my last fight. Go to my base and back does not solve the problem. Since I lost the fight due to not having enough powerful characters, I can't win it even given another chance. Not sure if this will happen again and again, if so my rift score will drop forever... so I have not tried another fight yet.