The issue is that ‘shapes’ on reports need to be placed first in their section (first from top to bottom) for the PDF printer to be able to display the text over the shape. It’s a back to front thing where ‘back to front’ corresponds to ‘top to bottom’ on the AX report section.
Source:
http://gatesasbait.wordpress.com/2008/09/08/report-shape-control-issues-with-pdf-printer-class-in-dynamics-ax-4-0/