Save As corrupts pdf file

Installed a trial of PDF Fusion a day or two ago. This is my first use.

The file is a pdf I downloaded. http://www.health.gov.bc.ca/library/publications/year/2013/MyVoice-AdvanceCarePlanningGuide.pdf

It displays OK in Adobe Reader and loads and is displayed correctly in PDF Fusion.

I Save As to create a working copy. The pdf still open in PDF Fusion displays corruption. And reloading the Save As file also displays the same corruption.

The document has a total of 56 pages, 4 of which are unnumbered (3 at the front and 1 at the end). The document looks fine (but could have less obvious corruptions) up to page number 33. I am using the page numbers in the document printed on each page (and this page number works in Adobe Reader).

Page 34 starts OK. The page title and section title are correct and the first 2 paragraphs are displayed correctly. The third paragraph loses the first letter of 2 of its sentences, and the whole paragraph is spread out (similar to full justification) with spaces between most of the letters (perhaps some sort of kerning problem)  and some letters on the right, lost off the page.  The rest of page 34 looks OK. Page 35 has about half of the page messed up with letters all over the place, missing sentences, and possibly other problems.

Page 36 is almost correct, but some very small fonts are spaced out. Page 37 has 4 sentences with weird kerning (letters spaced out). After that, there are good and bad pages up to the end of the document.

I suspect that the document was originally compiled from several other documents. That may or may not be relevant.

Any suggestions?