- Create one true/false question
- Set "correct answer" to true and then the true and false feedbacks.
- Save the question
- Everything is ok (question_answers show the correct "fraction"
- Edit the question, the "correct answer" defaults to false (easy to forget).
- Correct answer should be gathered correctly
- If you save that edited question, the answers "fraction" gets interchanged, so the initially correct answer becomes the incorrect and vice-versa.