
Ari W. answered 04/12/19
Published Artist Teaching Graphic Design & Photography
You've done everything right - if the PDF looks right, that's all she should need, and you could preserve the AI editing capabilities. I would not turn over .AI files to a difficult client or to someone who is not skilled in Illustrator. Saving to an older version of Illustrator can help at times, or even using EPS.
To solve her issue ask her to take a screenshot of what's not displaying correctly - there could be problematic artwork in spite of all you've done. I use Astute Graphics' Vector First Aid to clean up files and reduce their complexity before sending them on to customers and vendors.