It is a known issue, especially in some older versions of Word, that the "x" and/or "y" part in "Page x of y" may not work properly; see the article at

http://word.mvps.org/FAQs/AppErrors/PageXofY.htm.

However, the issue discussed in the article refers to the total page count, where "y" is the NUMPAGES field. In your document, you are using SECTIONPAGES for "y." (You can verify that by displaying field codes; use Alt+F9 as a toggle.) It is still worth testing the workarounds mentioned in the article.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional