I'm not sure why, but after a quiz, when I get more than one wrong, it only shows one in the "terms you missed" section at the bottom. How am I intended to use that section?
(If it helps at all, I tend to click "ask again" on everything I get wrong.)
There is no need to click the "ask again" - this basically resets the question if you want another try at it without recording having missed it. Any terms you miss will be automatically reviewed at the end of the quiz.
If you miss a term, click that button again, then get it right next time, it will not appear as a missed term.