Disappearing notes on iPod Touch

I have used the Notes app forever. A few months ago, I enabled the iCloud sharing of the Notes so that I could see and maintain the Notes on my various devices (mainly Touch, iPad2, and iPad mini). A while later I noticed that new notes created on one of the iPads never made it to the Touch. Also, sometimes a document that was on the Touch one day disappears the next (although it's still on the iPads). I don't understand why this is happening only to the Touch.

Any thoughts?