I can't really remember how this worked in Moodle 1.9. That is ancient history as far as I am concerned.
I don't think the teacher comment is significant. Can you try this alternative test:
- Create a quiz containing two questions on two separate pages. Q1 Opaque, Q2 true/false, on two separate pages.
- Attempt the quiz as a student, answer Q1, then go to the next page, but do not submit the quiz.
- Log out of Moodle and close your web browser completely.
- Go back into Moodle, log in again, and resume the quiz.
Now can you see the responses to the question?
That is, I am guessing that your question engine does not get this bit right: http://docs.moodle.org/dev/Open_protocol_for_accessing_question_engines#Question_sessions_and_the_reproducibility_guarantee (but that is only a guess.)