Ok, I know this issue was brought up in the past and Jpod101 solved it by having 2 versions of PDF - Lesson note and Lesson note lite.
However, I don't think this is a good solution, the lite version has a huge downside, the display is ugly and not elegant. Having used to study from the old PDFs under preview, those old PDFs are definitely more elegant under preview than the current one.
More importantly, there are some lessons' PDF that offer no lite version, that essentially force a Mac user to use Acrobat reader to read the PDF. Reading PDF with Acrobat in a Mac is slow, the font is even more ugly than the lite version. This make reading very difficult, especially if you were to read lessons with a lot of hiragana and katakana.
I just started a thread in some major Mac forums including Apple's discussion rooms seeking for help to solve this problem. I hope Jpod101 crew who is involved in making the PDF can help and participate in providing information like how the PDF was made and what program was used etc... to help solve this problem once and for all.