ok...it is the default setting then....
You can check the drafting standard from...FILE/UTILITIES/CUSTOMER DEFAULTS/DRAFTING /GENERAL /STANDARD...by default it is ISO(shipped).
i forgot to mention one thing...it seems to be a flat pattern drawing (anything related to one of your older threads?) . did you change the flat pattern drawing settings (if i am not wrong Dave suggested some settings in his reply)
I would recommend setting up your environment according to your company drafting standards.
Once setup correctly, each and every drawing will be created to your requirements.
How are you creating the PDF? Ensure your chosen method is setup correctly. I have tried all three of the methods shown below and can see a diffierence in line width between outline and dimension
File-->Export-->PDF (do you have single width set here? Try Standard Widths)