An incorrect page size is selected after you undo or redo a page size setting in Microsoft Publisher.
This problem occurs because Publisher does not have a value in undo or redo logging that records the page size. Therefore, Publisher tries to use an existing page size based on the raw data after you undo or redo the page size. Publisher 2010 uses the first data that it finds as the page size.
To check the page size, click Size on the Page Design tab.