[kawls]

I load and store my books in Calibre and then sideload them to a Kobo Clara HD. For months, I’ve used the fetching command on the Calibre annotations plugin to sync book annotations made on the Kobo device to the book’s parent copy in my Calibre library. Last night, the Kobo device stopped recognizing these annotations, although Calibre still sees them and they’re still in the book’s metadata. The Kobo device will make and sync new annotations, but it does not find the old ones, even though Calibre matches those books with older annotations to the copies on the device, showing a green checkmark in the “In Library” column.*

Can you help me to understand why the Kobo device is not recognizing these annotations, and how to resolve the bug? *

Steps taken so far:
Updated metadata on device through Calibre…bug persists.
Repaired the device’s Kobo account and then sideloaded…bug persists.
Factory-reset the device through settings page and then sideloaded…bug persists.
Reset the device with new Kobo account and then sideloaded…bug persists.
Downgraded Calibre to 4.21 and then sideloaded…bug persists.
Factory-reset the device manually and then sideloaded…bug persists.
Imported library to new installation of Calibre on different computer and then sideloaded…bug persists.*

Here are my specs:
Kobo Clara HD 4.22.15190
Calibre 4.22
MacOS 10.15.4 *

I’ve attached three (public domain) epubs to this post. Silas Marner contains a new annotation that both the Kobo device and Calibre annotation plugin recognize. The other two books—Whirligigs and The Adventures of Tom Sawyer—contain older annotations that Calibre sees but the Kobo device does not.*I’ve also attached a debugging report for fetching annotations from these three books. The fetching process found only the new annotation in Silas Marner, returning no results for The Adventures of Tom Sawyer or Whirligigs, even though they’re matched in the library. If I delete those two epubs from the Calibre library, move their copies from the Kobo device to my desktop, and then load them from the desktop into Calibre, the annotations plugin does find the annotations.*