Not all that weird. There were fairly large changes made in the basic document structure in Word 2007 that have continued through to Word 2016 (the Ribbon versions).

One of the basic ones was changing the line spacing from single spacing to "Multiple 1.15."

Why this would only show up in the display but not the printing is very curious. Again, I suggest attaching some samples. If needed, you could fill with dummy text. The rand "virus": or how to insert dummy text into a document by Suzanne Barnhill