Actually, it is tricky to reproduce, and it was tricky to find it.

In standart code for PaginationApp.java we will need additional line: System.out... like this:
Button setOldPageFactory = ButtonBuilder.create().id(SET_OLD_PAGE_FACTORY_BUTTON_ID).text("Set old page factory").build();
            setOldPageFactory.setOnAction(new EventHandler<ActionEvent>() {

                @Override
                public void handle(ActionEvent t) {
                    System.out.println("Old page factory set"); - here, to note, that changing was called.

To reproduce:
run application.
Set new factory. (notion - a word "new" in content of pagination).
Click on control's content to receive focus on Pagination control.
Move mouse on setOldFactory button
Now we need to do 2 things parallelly:
1) press "RightArrow" key on keyboard
2) click Button "Set Old Factory"

That is: changing factory, when you do switching pages.
I see:
In output: message "Old page factory set"
In pagination: content of new factory.
But, if I switch page, old content will be shown, according to the current old factory.

It is shown on the attached movie.