I seem to be having the following issue recently.
When adding a gallery to favorite it shows a note also exiting for the gallery even if one was not added.
When attempting to add/view notes from within a gallery it displays a note of Undefined. This happens both if there is a note present and when there was no note added.
It is still correctly able to add a note, which appears on the favorites page, but any notes added are unviewable from within the gallery.
Example below, i have not added any notes to this gallery, i only added it to favorites.
When i do add a note it still shows a note as undefined, but when i check the favorites listing page it successfully shows the note I added.

This is on v2.2.0f using chrome with tampermonkey.