Well, it seems something has changed. Outlook is now working for me this morning without a new update; I'm now running 16.53 (21082406). And while I'm able to use Outlook now there seems to be some ghost messages here and there that are blank.

New beta upgrade from MSFT today. I am now running Outlook v16.53 (21081705) and the problem is still happening for me. Any other news out there?

I have the same issue. I'm running the most recent MSFT Office 16.53 (21081500) update from the beta channel and the issue is still occuring. Currently using Outlook inside Parallels as a workaround.