When exporting an InDesign file to an accessible PDF file (tagged PDF), if any endnotes contain hyperlinks, the tagging structure is messed up. Starting with the first hyperlink (not the links for the endnote references), all of the endnotes from that point on are in the link tag for that first hyperlink. I encountered a very similar bug a few years ago when exporting to the EPUB format with documents that contained endnotes that finally got resolved a year or so after the bug was reported.