So you saved with the option "Preserve Illustrator Editing Capabilities" turned on?
Did you edit the resulting PDF file in another application afterwards?
Yes "Preserve Illustrator Editing Capabilities" turned on.
I don't edit pdf with other applications
Hide site suggestion, always, always save an ai file before saving the pdf and use only the ai file for editing. You will heave less headaches. Won't get rid of all the headaches, but most of them.