I have a similar problem witch happens in my windows 7 laptop, but not on my iMac at home.
The notes sometime disappear, but also sometimes when I get back to the though I can see the not again, but most of the time the windows note is frozen. I cannot see the cursor and apparently I can not edit the notes. But if I try to type something, even without seeing nothing happening, the words count continue to increase and eventually if I come back to that thought the note was updated with the words I have typen. Very annoying...
The bottom line is that currently the use of the notes is impossible.
This is already happening after a dozen updates.
Thanks in advance,