Wrong answer in lesson multiple choice question gives points

To reproduce:

1. Create lesson with Custom Scoring set to No
2. Create multiple choice question that have four answer options,
   one correct (1p) and three wrong (0p each)
3. Login as a student
4. Do the Lesson and give a wrong answer
5. The system says "You have answered 1 correctly out of 1 attempts"
6. When checking the question, note that all answer options, also the first one, are set to "0" score