This changes the context of a lot of things, but what bugs me the most...
What about dime's premonitions? The last idea was that he wasn't seeing the future, but instead the past of the other side world, because our Yuria's world is 2nd and is offset in time (is younger). But how does that make sense if the other side is the copy?
P.S. And there was evidence of the 2 worlds being merged, mainly with the contents of the Otherside overriding our world. So maybe that's bootleg causality messing with our world, trying to make Otherside's history non-meaningless? Or the will of our world doing the same.