I discovered my error and deleted the incorrect entry.
Now, that student does not get a total for quiz points. The category total cell will not update. It also has the "orange" highlighting to indicate that it held a manually entered grade.
I have checked every setting I can find and nothing is locked. The calculations work for other students in the class.
This is a big problem, since it is pretty easy to get off a column and type numbers where you don't intend to type them! I normally use the assignment grading interface when possible, but quizzes require manual entry of scores in the gradebook.
How can I return the gradebook to automatically calculating the category total for quizzes for my student??