The quiz is NOT set to adaptive mode
The behavior of the problem is: deferred feedback
Yes the penalties are set to zero
The problem has 7 parts. Most parts are algebraic formulas. The part that I think might cause it, is not at all trivial, and needs to do a lot of checking of all possible answers in order to give partial credit.
BUT ... irrespective of it's complexity ... I don't understand that it can give full credit and mark something as wrong, and also mark everything as correct and not give full credit. That doesn't make sense.
I was wondering if anybody had ever run into such a problem, or if it had been a forum item. So if you think it has never been discussed in the forum I don't have to look any further. Thanks, Dominique.
If I have some time in the near future I boil down the problem to just the essential part and send an XML file so that you can see that it indeed happens. And maybe someone can figure out why.