I already got all the emblems and spent them (there were no unlocked skills in my tree), but now I got to a shrine of Mab, it offered me an emblem and then I got the "first emblem of mab" achievement, and following it the achievement for getting all emblems. The emblem didn't have a "spend" option (and when I checked I see that indeed I already have the "spent first emblem of mab" achievement).