GitToDeChoppah iOS MS Word has a reset credentials in Settings. I had to use it to fix a MS Office Mobile installation once, and continue to use it when I run into issues. I requested the same for Outlook in UserVoice.
We've had a few users with this issue in Outlook Mobile on iOS (unknown if Android has the same issue) and continue to get tickets for it. It hasn't affected the entire population so far.
In our case, Support identified an issue with the Conditional Launch Max PIN attempts/Wipe Data Action. My current solution removes them from the problem APP and assigns a temporary APP with the Conditional Launch Max PIN attempts/Reset PIN setting. I have the user logout of Authenticator, delete Outlook and Authenticator from the device choosing the option to remove the creds from all apps on the device. I also revoke the user's auth refresh tokens using PowerShell to be sure. APP can take 24h to apply so nuking the creds could force a completely new policy read. This causes other apps to require a reauth, including some desktop apps. User downloads and configures the apps as new, and then I move them back to the original APP.
MS says they are issuing a hotfix to developers, meaning it's not going to be solved quickly IMO.