What the subject says. As a sorcerer I have 20 points extra mastery for purple. However, it is not counted in the scrolling numbers in the overview screen. And as far as I can tell from the totals, I don’t think it’s showing there. Leaves the question: are they active at all?
It may apply as the match starts, like how having +25 from a team won’t show on the hero page even if it is your defend team.
But that makes no sense (or is inconsistent at least) because it applies in general for as long as this class is selected.