Ribbon greyed out when document opens

I am running the latest version of Word on macOS Monterey. Every time I open a document in Word (existing or new document), the Home ribbon (which appears by default) is greyed out. In order to use the ribbon, I have to either click a different ribbon tab and then go back to Home, or hide the ribbon and then show it again. See attached screen shot.

Does anyone else have this issue, and/or does anyone know a fix for it? Thanks.