In InDesign 19.4 x64, when an epub export is created for a book (.indb file), page navigation links restart at page 1 for every document (.indd file). The toc.xhtml file looks okay despite this, but in the document xhtml files, the software is treating duplicates as non-unique and appending a sequence number to them. As a result, many of the links in the toc.xhtml file are broken. I've attached a text file showing portions of the relevant xhtml files illustrating this problem.

This is a major issue, because some epub distributors catch the error in validation and prevent the book from being uploaded. Amazon KDP doesn't care (for now), but IngramSpark does. I have to unzip the epub, manually remove the page navigation from the toc.xhtml file, and repackage it in order to distribute the epub through them.

Notes:

1. There is another request mentioning that the page numbers should reflect the page numbers in the book. If that were implemented, this problem would probably go away. However, that request indicates that the links work. Clearly, in my case, they do not work.

2. There is another request reporting that the Page Navigation checkbox does nothing. I've verified this. I tried to resolve the issue by unchecking Page Navigation, but the page navigation code was inserted into the files anyway.