Fix Microsoft Authenticator for iOS with Outlook.com
Since quite a while I am using the Microsoft Authenticator for iOS successfully. Since a little while, maybe iOS 13, the notification on the lock screen of my iPhone shows up two times. This happens only for my Outlook.com account. So not for several other (work, CSP, etc.) accounts that I am using with the app.
Yes, I reinstalled iOS.
Yes, I restored the phone.
Yes, I removed the authenticator from my Outlook.com account and re-added it.
Yes, I reinstalled the app (and reset all the account on it - what fun).
Yes, I have done same w/o and w/iCloud backup.