Text overlaps in .pdf documents

What causes some text to overlap when reading a .pdf in LibreOffice Draw? (Why documents should open in Draw is a different matter entirely. I’m using LibreOffice 4.4.2.2 on Ubuntu version 15.04.

This may help: http://askubuntu.com/questions/740887/libre-office-modifying-producing-overlapping-text-which-was-from-ms-word-documen