Hello Anna,
I do not have detailed information on the bug, but have you tried selecting the output cell where you have the plot and then going to File > Print Selection? In my system, the default is to print to file 'print.pdf' in my home directory. There are options in the dialog box. Additionally, the options under the menu: File > Printing Settings can be used to fine-tune your PDF (orientation, margins, etc.).
I use this to prepare presentations of my results and I find it acceptable. I have tried Exporting to PDF but I don't always get good results (especially if the output is large). Using Print Selection I have been able to print large outputs (entire lists of graphs that I produce in one cell). With minimal adjustments of the ImageSize for the plots, I can even get multiple-page PDFs with reasonable page breaks.
Hope it helps,
OL.