To replicate create a course on 10x nightly branch
Add 1 student
Create a gradebook with 2 categories
In the first category, make 1 gb item and assign the student a score of 25
Average score will show properly as 100%
Create a T&Q exam worth 100 points and have the scores sent to gb
Have the student take the exam and score perfect
Go to GB as instructor, average score will now show as 500% as its calculating the unassigned category item even though it is not selected to do so.