Hey Greg!
Any news on this?
I can also share, that it's not related to Edge - the same happens in Chrome, when try to unlink on the specific page you are taken for this task (https://www.msn.com/de-de/feed/personalize/settings).
A call is made to https://www.bing.com/accountlinking/delete and it fails with a CORS error.
Best Jörg