links no longer working in embedded pdfs

Links in embedded pdfs used to open an "Open Web Page" dialog box.

Everything seemed to work perfectly fine over the past several months, until today when I went to click on a link, and now the dialog box no longer appears, and it seems linking is broken?

(I have not changed any of the code)

Now, before clicking any link, the cursor mouseover changes (as normal), but after clicking any link, the pdf is surrounded by a thin blue border, and none of the links show mouseover behaviours anymore or are clickable.

If I open the pdf files in adobe, the links work perfectly.

Did adobe change something about link behaviour?

For example, the coloured bold names on the left column should all be links:

File on Website

They work in the attached pdf file, but no longer work on the site.