Hmm, yea apparently on patch 2.3 the power-ups card is already given at the beginning even before doing the tutorials.
And also, there's no way to get rid of those free power-ups as well.
So I guess, like what some people here said, try to refill those empty hotkeys.
You should see the option like this:
If you don't even see the options, then I agree that this is such a big mystery .__.;;;
It could be another form of mysterious bug that L3g3nd encountered.