Let me illustrate this issue using an example regarding the display after the quiz is graded for a student:
Moodle 1.9.5:Marks: 60/80
Grade: 75 out of a maximum of 100 (75%)
Moodle 2.0 (RC1):Marks: 60/60
Grade: 75 out of a maximum of 100.00 (75%)
60/80 has become 60/60 on upgrade which gives the false impression that it is 100%. Since, it is upgrade, shouldn't the numbers be identical before and after the upgrade?
If there are large number of quizzes and/or attempts, this upgrade can create such problem for all.