[bug] the quest exp unstable?

I am at level 11 now.
Every quest in my list display only hundreds of exp, seems not a 7x exp. Even quests display thousands exp when I accept them, however I get only hundreds exp when achieve it.
That's abnormal , because I did got thousands exp per quest today before level 10.

is it a bug? or some mechanism of Icecrown server?
look for your help. thanks.

Have you tried right-clicking the experience bar and seeing if you are playing at x7 rates?