I made a map including 3 levels of zoom as shown in the screenshot. The problem is that whenever I save the map to a PDF, the layout of these maps is changed seemingly random. 
I have a hunch that it has to do something with 'Lock layers' or 'Lock styles for layers' functions, but they don't really seem to work. Right now, I have the lock layers box checked on all maps and Lock styles for layers unchecked.

