@jawall, @KellyEyre, and @Ann82 ...
I do know that recently there was an issue with the bottom scroll bar of the "Grades" page which was detailed in:
Gradebook scrollbar is cutting off the last row of... - Instructure Community - 601863 (canvaslms.co...
According to the above document, that issue has been resolved. However, I do not know if this has now resulted in what you are currently seeing. My suggestion would be to contact the Canvas Help Desk staff to report this new behavior. If the issue has already been reported, they will attach your name to the existing ticket so that you can be notified once this new issue in "Grades" has been resolved. You can submit a ticket following the instructions in this Guide:
How do I get help with Canvas as an instructor?
I know this isn't an exact answer for you, but I hope that this will help in some way.