When "saving as" a PDF in Illustrator, close PDF.
When "saving as" PDF in Illustrator, close the PDF down, leaving the natural AI file open. I have made edits afterwards thinking I was in the original file only to close down the edited file then reopen to the AI to add a new round of edits and the bloody AI file doesn't have the first round of edits.
I file share with other authors who have done the same thing. THIS COULD LEAD TO A VERY EXPENSIVE PRINT RUN. ALL other software converts and leaves a file IN THE FOLDER not on screen to be edited.
Rafael Ocaña commented
I understand Illustrator opens PDF natively BUT I also think PDF should be an export option.
That way we should be able to edit only the original. And never again be mistaken.