Printing in Mail Cutting last line on page in half

I have a friend, using a Macbook Pro 15", who has noticed since the last upgrade to 10.9.4 that whenever he prints a multi page document in OS X mail that the last line on the page prints half on one page and half on the next. Default paper size is A4 (standard in NZ). Text also splits if print to Preview. Discovered it the default paper size is changed to US letter that text no longer splits.

To try and find out what could be causing this I tried to duplicate the problem in my MacBook Pro 17" also up to date with OS X 10.9.4. On my machine with paper default set to A4 prints multi page document without cutting the last line, i.e., paginates between lines. Changed my default us US Letter and it split the last line in half. Same problem but with different form default.

Any one know what setting is controlling whether it paginates between lines or on the line? How to stop mail from cutting the last line on the page up with half on each page?