In Mark Dever's Nine Marks of a Healthy Church, I just noticed that chapter one goes p. 41, p.40, p.41.
@Jonathan Bradley This is deliberate.
In the paper edition, page 40 is mostly blank. Using a large blank space to mark off a new section doesn't work well in a digital book. So we placed the text of page 40 after the heading on page 41.
We occasionally make small formatting changes like this for a better user experience. We still keep the original page numbers, though.
That makes sense. Thank you for responding.