I have noticed that on 2014-12-17.
It seems to be only in opera 12 so it's ultra low priority, if it does even deserve to be fixed.
I take any page with ratings (in either sidebar or main content).
If I click any rating, the new rating is well submitted but then the display is not updated (and its state is little bit strange on hovering).
For the display to update properly (voted stars to show my new rating) I then have to click the body, for instance.
Something must have changed in the ratings macro (because it's either in main content and sidebar the same) that displays those stars or in the mouse event management (because it's updated when I do some other click, like if there was a queue of events that would not pop).