"Undefined property: 'endnotes'" - valid epub3 files rejected by Kobo store

[AudreyLBE]

Kobo has rejected several books with the error:
OEBPS/Text/notes.xhtml(10,33): Undefined property: 'endnotes'.
I don't have any further details.

They are reflowable epub3 books with numerous endnotes and they validate with epubcheck v4.2.2 and Ace by Daisy1.1.2.

The endnotes are in their own file notes.xhtml, in a
<section epub:type="endnotes" role="doc-endnotes">
and each note is also defined:
<div id="footnote-1" epub:type="endnote" role="doc-endnote">

An example is isbn 978-2-490431-03-8 title "La Famille de l’antiquaire ou la belle-mère et la bru" but I can't attach it here for copyright reasons. I previously encountered this same problem nearly a year ago. If I recall correctly, to get around the problem the last time I changed all the "endnotes" to "footnotes" so the client could get the book available for sale, and I'll do that here too but this is a hacky workaround, not a solution.

This looks a lot like the previously identified problem of validating with an outdated version of epubcheck, eg :
w3c/epubcheck#714