This issue may be present when using Adobe Reader/Acrobat with Sarafi on Mac OS, or if you're using Firefox regardless of OS.
Safari on Mac OS with Adobe Reader/Acrobat:
Some users might encounter a problem when they save the PDFs in Adobe Reader’s preview in Safari. Once the PDF is saved, the file is corrupted and cannot be opened. If you encounter this on their Mac, go to your Library folder (located in their main file directory) and then the “Internet Plug-ins” folder and delete this plug-in:
You should close Safari and then restart it. Once you attempt to save the PDF, again, it should save correctly without being corrupted.
Firefox, regardless of OS:
Firefox defaults to previewing PDFs in its own built-own PDF viewer. However, the “download” option in the viewer may corrupt interactive PDFs. To remedy this, go to "Options", select “Applications” and then change the option for “Portable Document Format (PDF)”. The default option will say “Preview in Firefox” and should be changed to “Use Adobe Acrobat (in Firefox)” on a Windows Machine, while Mac will likely just have the option “Use Adobe Reader”.
You should then be able to open a PDF from Blanchard Exchange and save it correctly.