Recently I remember a question in the Global Challenge which asked what team a player was on. It came from a quiz in the NBA 2000-01 subcategory of NBA By Season, but all that was provided was "Basketball : NBA By Season". Neither the question nor the quiz title mentioned the year, and you can't get the quiz's introductory text. http://www.funtrivia.com/trivia-quiz/Sports/Players-and-Their-Teams-24664.html
was the quiz. It's true that Damon Stoudamire never played for the three incorrect answers, however (and I still would have had a 25% chance of getting right if I had the year). I vaguely remember encountering the same issue for an Olympics question.
It appears this is only an issue for the special (sub)categories. It appears it shows the second most specific subcategory. For example, I did the People Themed E-K set, and two questions were in the "Hanks, Tom" and "Ford, Harrison" subcats, and it showed "People Themed E-K" as the subcategory. Another question was in the "Hitchcock Taglines" subcat, and it showed "Hitchcock, Alfred".
The regular categories properly show the most specific subcat as far as I can tell.