Steps to reproduce:

1. In the question bank, create a single question 'Test question' in 'Test category' with two versions, v1 - ready, and v2 - draft.
2. Create a quiz, set to pick a single random qustion from 'Test category'
3. Attempt quiz as a Student.

Expected result: Student gets a quiz attempt with v1 of Test question.

Actual result: Error "There are not enough questions in Test category to create the question Random question (2)."

Discovered by Martin Latschenberger and reported in the quiz forum: https://moodle.org/mod/forum/discuss.php?d=455845