Duplicating quiz with random question has exponential questions growth

Reproduction steps

1. Install Moodle
2. Create a course
3. Go to Question Bank and create a "True/False" question in the course's default category
4. Create a quiz in the course
5. Add a "random question" to the quiz using the course's default question category
6. Duplicate the quiz
7. Duplicate the quiz again
8. Duplicate the quiz yet again

Expected result

The mdl_question table contains 5 rows:

• 1 row containing the "True/False" question created in step 3
• 1 row containing the "random question" added in step 5
• 1 row containing the "random question" from duplicating the quiz in step 6
• 1 row containing the "random question" from duplicating the quiz in step 7
• 1 row containing the "random question" from duplicating the quiz in step 8

Actual result

The mdl_question table contains 9 rows:

• 1 row containing the "True/False" question created in step 3
• 1 row containing the "random question" added in step 5
• 1 row containing the "random question" from duplicating the quiz in step 6
• 2 rows containing the "random question" from duplicating the quiz in step 7
• 4 rows containing the "random question" from duplicating the quiz in step 8

The number of questions created through duplicating the quiz seems to have exponential growth.