Hawke I think i may know to what you are alluding to, when the Dasati and Midkemia worlds somehow seem the same.
When Pug and his entourage arrive in the Dasati realm and hook up with the Dasati that turn to the good side(*Luke I am your Father....*) he retires to one the rooms and is atonished to see how similar the scene was to that of Crydee when he was young. I think this is when he realises that Dasati and Midkemia co-exsist in parallel universes...well thats how I figured it made sense if any others can shred some light be much appreciated....
I have literally just finished reading Into a Dark Realm and I think I've found what you were talking about, in my copy (Hardback) its on page 328 and its when the party are in Kosridi in the Dasati realm...they go onto a parapet of a castle or something and the book reads:
Pug could see the rolling vista of the town beyond the castle, and the ocean below that. Then it struck him that there was something familiar about what he was seeing.
Nakor said, "I've only been to a place like this once before, years before when Prince Nicholas had to sail after..."
Pug cut him off "Its Crydee," he said softly.
"It looks a lot like Crydee," said Nakor.
The book then says (A couple of sentences later)
"I don't know. In one sense, I guess it means we're back home, just on a different plane of reality."
Pug began asking Naureen and Martuch questions about the geography of the region and quickly came to understand that Kosridi was Midkemia, only on the second plane of reality.
Hope that helps people understand what I was getting at