LIGHTROOM 5.2: Image quality changes in jpeg print outputs when large border is used?

I am using LR5.2 and have noticed an issue with the Print Module where if you enlarge the page border (so the image shrinks on the page) there is a significant loss of image quality when you print to jpeg. I presume that the image shrinking has something to do with this - is this a lR issue or a user issue? Thanks.