This is not the problem, and it is correct. Different cores can have different speeds at a signle moment of time. Not all CPU's and mobo support that, but mine does. But, as I said, this is irrelevant to the problem reported.
Define 'should'. Why are the cores supposed to have the same clock rate? I don't see why that should be a requirement. I have seen intel xeon's with intel speedstep tech. years ago that just have the core that is under load speed up to its rated speed, and the others remain at idle...
Well, my pref. is that it showed at that place the actual current core speed, not the idle, max speed or stock speed, or max. overclocked speed.