Just tried gateway/quiz for the first time, and there scoring anomalies. Now this may just be because two of the four problems used the deprecated compoundproblem.pl macro, but I'm not sure that explains everything. Here are the previous answers and scores for one student.
previous answers:
score:
Aren't these blatantly contradictory? The previous entries show the student getting everything correct, while the score is 2.75/4.