Hi @KellySylte,
Is this problem still happening?
Are you using the zoom functionality built into your web browser? Are you using any of the zoom features builtin into your computer's operating system? Sometimes those options cause unexpected visual problems when doing something.
You might want to also consider disabling any third-party extensions/add-ons that you have in your web browser. They can sometimes cause conflicts.
Due to the sensitive nature (since grades are involved and potentially names of students) of the situation, are you able to record your experience and post the recording as a reply to your original question so that we can see what is happening and offer more help?
If you cannot record it (or at least, cannot do it easily) because names and grades, you should probably report this to your institution's Canvas team. If they are able to explain what is happening, they should be able to report it directly to Canvas Support.
-Doug