¿How to export PDF directly with embedded links from Illustrator?

Recently a new problem emerged and i am not sure what im doing wrong.
I work with packaging and once i finish the design i export it in PDF and send it to china for printing.
Years without problems por this last month, one of the suppliers told me, when they open the PDF file, links where required. This has never happend to me, they always opened it without a problem.
For now, my workarround is to save the file twice with "include linked files" in the illustrator save options.
After the save, i have to close the file, then open it again and than all files are embeded and than i can export the PDF with all the files included. This does not only clutter my workflow and is a great time sink, it also leaves file behind that have a great size and need to be erased constantly.

Does someone know a way to simply export the PDF and change something in the export menu in order for the images to be directly included in the final PDF file?

Thanks in advance!