Stress wrote:
In AC 18 and prior...
I could switch to different layouts by using the "Go to next Layout"
buttons or by using the view map.
The layout displayed would change and the "current"
view would be maintained.
In AC 19, switching to different layouts sometimes changes the zoom,
almost as if each layout had a "saved" zoom.
Is there a setting somewhere? 
Hi,
I've been looking for a solution to this unnecessary problem aswell! Your topic helped me search more thoroughly for the answer.
In your project, make sure all the layer tabs are closed (except one tab ofcourse, otherwise it will close the entire project). Once you've closed all the tabs, go to Options > Work Environment > More Options, and choose "prefer to open in an existing tab", not a new tab.
Now if you scroll through the Layout Book, the same zoom should remain for all the layouts you flick through.
Regards,
Mounir