[Introduction to bug, if necessary here]
I think you're the very last person who got to report a bug through the user group! (From now on we're asking everyone to report bugs for the New Gradebook through our regular Canvas support process.)
I was able to reproduce what you've described, but we'll need to confirm with the product team. We'll let know when we have an update, which will probably be next week.
Our team has filed this behavior as a bug. Watch the release notes for this fix to be updated in a future release.