WOC Trick

Can't speak as to why you received the results you did (and I'm glad you've reported this), but I'd actually try a different search using a dataset that actually annotates questions in the Bible, and intersect it with speaker data (so you could search for questions of Paul, or Barnabas, or Moses, or God, or David, or whatever).

The propositional outlines do annotate questions, but it may not be comprehensive (if the question fulfills some other propositional function determined as more salient than a question, it may not be annotated as a  question in the propositional outlines).