Steps to reproduce:

1. Login as a teacher and go to the question bank in a course.
2. Click the 'Create a new question' box and select "Select missing words".
3. In the Choices, type four words and add two words to Group 1 and two words to Group 2
4. In the question text box, type a sentence or two including the words, replaced by [[1]], [[2]] etc, corresponding to their numbers in the Choices.
5. Click the 'Save changes' button.
6. Edit the question, and make sure all the boxes contain the correct text.
7. Click the 'Save changes' button.
8. Attempt as student and click check. You will observe the box is either red or green and there is no text displayed in select box.