Page view changes when changing layouts - why?

A. Please explain further - are you talking about two different score layouts within the same project, and if so are they open in two separate windows or two separate tabs? Two monitors or one? Two separate projects open simultaneously?
B. As per the guidelines, please don’t cross-post the same thing in multiple topics. You posted exactly the same message here less than 24 hours ago, on a Sunday, on a Bank Holiday weekend.