Well, these are computers. They don't have a mind of their own. They behave deterministically according to their programming. So, while the behaviour may seem random now, that is just because we don't have enough data about what is actually happening.
You need to make more observations of what is happening, which you can do either by analysing the server log files (and Moodle logs), or by watching while the students attempt the quiz.
Once we know exactly what is happening, then we will know if there is a bug, and what to do about it.
You need to make more observations of what is happening, which you can do either by analysing the server log files (and Moodle logs), or by watching while the students attempt the quiz.
Once we know exactly what is happening, then we will know if there is a bug, and what to do about it.