Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
As reported elsewhere by EmilyS_726, see the updated version of the KB article at https://support.microsoft.com/en-us/servicing/os/microsoft-365/kb5002907-optional-update-for-out-of-date-microsoft-365-apps-installations .
In particular, there is an Important notice which describes how certain Office installations may become deactivated. The workaround is to reactivate affected installations (reinstall first, if necessary). The screen shot below is from the article.