Updater says an update for QOwnNotes is available. Updater says new version is 22.1.2.
Updater downloaded a 27,484kB file, then downloaded (another?) file of the same size, then issued this alert: "The downloaded copy of QOwnNotes is not valid and can not be installed. This could be due to an incomplete download or other network issue. Please try running the updater again when complete."
Identical results on two different PCs in two different locations.
The updater was still pointing to the old version which didn't match the hash of the new. Fixed it. Sorry for the inconvenience.
Sometimes, the impossible can become possible, if you're awesome!
Tested it, and it works. New file download size is 27,491kB.