When showing the quiz the extra questions are counted, but when clicking Take and going to node/id/take, the old number of questions are still visible - even after clearing the cache.

Comments

Same problem here. I have to edit and resave the quiz multiple times to increment the count.

This is by design. When the quiz starts, the questions and some properties of quiz remains persistent till the end of quiz to prevent producing inconsistent output due to changes made by quiz author along the way of quiz taking.

Please explain this as I'm doubtful about it working as intended.
After creating a quiz, I go into manage questions and add a question. I go to view to see if the question is added and the first one is.
I then go back and add another and back to view to see if it is added. It is not. I go back to edit and resave a couple of times and then it gets added.
No one is taking the quiz so I do not see what quiz would be preventing here.
In essence, for me, its not just the count but the fact that the question is not getting added at all.

I also notice that for the question to get added, it must be marked as 'compulsory'. What then is the function of the 'compulsory' checkbox if the questions must be compulsory to get added?

Unfortunately, I'm unable to offer any solutions or ideas but happy to test and report.

Ignore 'compulsory' question issue. I now understand how this applies to random questions as opposed to random order.