I had a similar issue with pickpocketing when I first started playing the game. I'd equip a ring with pickpocketing enchants and my success percentage would go down. I tested it again today, on xbox, and it no longer does it. Since, at the time, I could actually see the percentage values for success, I knew there was something wrong but it no longer does that.
I've installed a separate Skyim 1.2 to test both. The latest 1.2 not have the sneak problems I've reported at all! This is good news. : ) Sorry to those following, it took me awhile to download the update after suggestions in the thread.