Kobo notes working backwards after upload using KoboTouchExtended

[Liudprand]

I was having some problems with note cues in a particular book, which I need to be formatted as superscript.

In Calibre, they weren't superscripted, so I used Sigil to change the format of each one, using the superscript button in PageEdit.

I then opened the epub file in Calibre again, and all seemed to be well. But, after I uploaded it to my Kobo Libra 2 using Kobo Touch Extended, I soon discovered a problem. The notes now function "backwards" - i.e. the note preview, in the form of a popup, that is part of Kobo's way of handling notes (and very user-friendly) now only works when tapping the note number in the notes section. When you tap the corresponding note cue in the text, you don't get a preview - it just takes you straigh to the notes section.

This is doubly annoying: it not only deprives you of the preview where it would be useful (reading the note without having to go to the notes section of the epub), but delays your return to the main text after you've read a note by forcing you to close the preview.

It's hard - at least for me! - to know whether this behaviour originates from within Sigil or Calibre, or even Kobo Touch Extended; though the latter seems the least likely, given that it's never produced that problem with any other book I've converted with it. So, with apologies if this is the wrong place to post the question, I'd be very grateful for any pointers - specificically, how to fix the code in the epub file, and (especially) whether there's a way of doing so globally, rather than one note at a time.