I have been using Lightroom since version 2. I am currently using Lightroom 5.7, and haven't had any difficulty with print sizing. Have you adjusted the cell size appropriately. What OS, what printer, what have you tried?
Upgraded to LR 5 from 4. Now on LR 5.7... Having trouble with Print module. Preview and final result are not the same. The print is a cropped version of the preview.
Printer is and Epson Photo R2880 and Imac OSX version 10.9.5
Printer is an Epson Photo R2880 and Imac OSX version 10.9.5. and I have adjusted the cell size... Never had any trouble with previous versions of LR including 4.