Hi there. This problem is inherent to Acrobat and easy to solve. Open the preferences panel. Click on “Page Display” in the right column named “Categories”. In the “Rendering” section, make sure that “Smooth line art” is unchecked. There you are, the ghost lines should disappear. Although these lines actually do not affect the quality of your prints, they may raise some questions from unaware customers or authors. Hope this answer turned to be helpful. Please forgive my somewhat broken english, I am a “damn froggie”.