I have the same problem with 2.4.3. The PDFs load and work correctly in 2.4.2 and I did revert to that version. Of note is that in Preferences>Presentations, the order of the list of available controllers has changed. PDF is still there and checked, but it is not first on the list (as it was in 2.4.2). The other choices are grayed out, so not usable. I'm not sure if this might give the programmers a clue as to why the PDF section is no longer working. This is the same behavior that I saw in 2.4.1. 2.4.2 corrected the problem with PDFs and it seems to have returned.