As well as text items, ornamentation etc.
Isn’t this, what is happening?
A problem arises, when you delete pages and those frame breaks stay where they are. If you don’t want them to stay where they are, Dorico offers this little helpful tool, Swap with previous Page or Swap with next Page.
Swapping pages doesn’t affect manual staff adjustments.
Yes you are right. But: you can use this function cleverly to save a whole layout, by swapping pages one by one, thus moving a problematic page to the very end or to the very beginning.
Swap with Previous/Next Page mainly helps to ‘swap’ text frames or picture frames onto the next or previous page. Which leads to absurd results when the master pages are mirrored and, for example, page numbers are always on the outside and serial numbers on the inside… Conveniently, it completely ignores the layout.