For the benefit of people who can read code, here is the code that combines the quiz settings, group and user overrides: https://github.com/moodle/moodle/blob/a5f618d6a988547c31da73f2e5fff48c48c776fb/mod/quiz/lib.php#L289.
User override should take precedence, but there could be a bug.
If you think it is not working, the most helpful thing you could do is to try to make the simplest possible example that demonstrates the bug.
User override should take precedence, but there could be a bug.
If you think it is not working, the most helpful thing you could do is to try to make the simplest possible example that demonstrates the bug.