I have added my blog feeds to Facebook notes and it has happened to me twice that they stopped refreshing i.e. new articles from my blog feed were not being added to Facebook notes. If any user is facing the same issue, he/she can resolve this issue by refreshing the feeds and here is how you can do that.
Go to your profile page on Facebook
Under the Share tab, Click on Options.
Now click on Settings.
Click on Blog/RSS under Imported sites.
Click Update now.
Your feeds will be refreshed by now and Facebook Notes will show you the latest articles in notes which were not being fetched earlier due to some reason. You can resume your content creation & promotion work!