Joe, here is my post on the Excel forum. NOthing wrong with Excel, and when someone, (Not You), but others often do as 1st recourse, especially Micorsoft forums or Adobe with help from India helpers )....to reinstall an app or "delete your preferences" usually sign they don't know anything about issue.

https://answers.microsoft.com/en-us...eId=c62b31ea-ecd7-415d-8572-e1bf6b9f8202

Apparently some new nuisance from Excel Microsoft, but if you are getting this, then maybe Apple in the mix too forcing them? Who knows. Super annoying.. I'm not with Big Sur yet.