Sorry for the poor screen shots. I try to illustratrate as below:-
Master A: X'mas Tree
Master B: Candy
Case 1: If page 2 applied with Master A and page 3 is applied with Master B. Result is the full spread is Master A (X'mas Tree)
Case 2: If page 3 applied with Master B and page 4 is applied with Master A. Result is page 3 (Candy) and page 4 is (X'mas Tree)
Why Case 2 cannot get the full spread Master B (Candy)?
I hope this will be much clearer explanation of my problem, any help is greatly appreciated. Thank you.
Now I'm totally lost.
Did you check to see if the frames on the Christmas tree graphics cross the spine on the master page, as I suggested? An object that is even .1point over the line will be on both pages, so when you apply the master fo either half it will appear, just as an object that extends beyond an outside edge will appear on the pasteboard.