We are having this same issue and our faculty are very upset. We have had at least 10 cases this week of courses that have the Course Total as overridden and students are freaking out. To fix this we go to the database and manually change it so that the column is no longer overridden.
What we would really like to know is what causes this. It happens with random columns and like Sal it doesn't always happen to an entire column.
Any thoughts on what causes the column to become overridden randomly?