Testing version: 2.0 (10688)
What were you doing: Editing a note in a separate window, then closing the note when I was done writing.
What feature did you use: Note editing
What happened: The most recent changes were unsaved and therefore lost
What did you expect to happen: Changes to the note should be saved so that data loss does not occur.
An easy way to test this is to create a new note in a separate window (⌥⌘N), type something quickly, then close the window with ⌘W. When viewing the newly created note in the main app window, its contents will be empty, with whatever you quickly typed gone.