I have noticed that when I open certain PDFs in illustrator there are several missing shapes. I don't quite understand why this happens and if anyone can shed some light on the issue would be great. Note that opening the PDF in your defauly browser or in Acrobat always works perfectly fine.
PDF in Browser:
Notice how large part of the design is missing when I open the file in Illustrator. The bottom design is entirely missing and the stick figures in the first design are gone as well: