Hey everyone, quick update on this.
It appears to be the combination of two things (which has made it a bit tricky to track down):
- recent updates to Office are installing a new version of the embedded web browser (WebView2, based on Chrome), and
- a change with Google’s security practices involving embedded browsers.
Anecdotally, it also only affects some types of Google accounts or is, perhaps, being rolled out incrementally. (I do not experience the issue on 3 of the 4 accounts I’ve tried.)
Incredibly, it’s not clear yet what we can/should do to actually get around the problem. It looks like it will ultimately need to be resolved at the Microsoft/Google level.
Until then, one possible mitigation might be to remove the new WebView2 from your system – though I don’t necessarily suggest doing so because I don’t know what else on a given user’s system requires it. But if someone’s willing to take the chance, you can go to Settings > Apps & features and look for Microsoft Edge WebView2 Runtime in the list and uninstall that. That at least seems to have worked for me.
I’ll keep people updated as I learn more.