Word itself warns you that there can be issues converting from PDF to Word for PDF documents not generated by Word itself.
While I understand the convenience, if 100% accuracy with regard to original content must be preserved, then use a PDF reader only to read PDFs when that's the case.
Brian - Windows 10, 64-Bit, Version 21H1, Build 19043
It is better to be hated for what you are than to be loved for what you are not.
~ André Gide