I have 4500 hit rating. That's 13.24% spell hit. I have 260 expertise. That's .76% hit. So I have 14% hit rating. But if you look at my armory you'll see that I "have" 14.76% hit rating. What it looks like is happening is that the game is pulling my combined hit chance from the spell tab (Which is just displayed as 14%) and then again checking for expertise to make sure it adds it on hit rating to display the "right" hit rating value.
No idea how long this has been going on, but I know that the draenei hit racial was fairly recently (re)fixed to display on the armory again, and I'm assuming that this is when the expertise problem occurred.
Somewhat comical for me because I had been armorying a few people, and I was balking at how most of them were grossly over the cap. And now it makes sense.