It's a little complicated.
First, you must have spreads checked in the print dialog box.
Then turn off Allow Document to Shuffle and Allow Selected Spread to Shuffle.
Then, you need to separate the left-hand page from the right side island spread
Then you need to drag the page that used to be on the right side, back onto the right. (It may have moved over to the left of the left of the spine.)
And then separate the right-hand page from the next left side spread.
It should look like this:
Pages 5-6 are the right side with the extra fold.
Pages 7-8 are the left side with the extra fold.