It is very weird indeed. I was looking around to see alternative meanings of the 2 of cups, but it's very interesting that they won't unite, but still, they tell you of a union. The thing that popped into my mind while browsing through meanings was the element of surprise. I did a deck-to-deck reading once and at that moment I realised that I left out the older deck for the newer and there were some ill feelings between them, but now I think it's ok, as one only works for other people and the other one for me (both are RWS-s), and I don't want to get a new deck because I have these to in such a harmony I don't want to ruin. Maybe it's about ying and yang in your deck relationship too, I would suggest a reading to elaborate their message. Good luck, and let me know of the result, because it's a very interesting matter for me. :-D
Sonki