We received reports that the drag and drop matching question type does not always save submitted answers when the answer contains an image or a table. Reproducing the problem with images has been tough but I have reproduced the problem with tables several times.

1. Create a quiz.
2. Add a drag and drop matching question to the quiz.
3. Make sure the answers contain tables at least 2x2 or 3x3 in size.
4. Attempt the quiz. (User role does not matter; the problem is occurring for teachers and students.)
5. Drag answers for each part of the question. (see first screenshot)
6. Click Next to proceed.
7. Moodle tells you that the question is incomplete. (see second screenshot)
8. Submit the attempt.
9. The quiz attempt review shows that some of the answers saved and some didn't. (see third screenshot)