Login Prompt stays after unlocking Macbook using Touch ID
Solution 1:
I suspect this can happen if you use network authentication (like Active Directory), and your network password was changed. Your fingerprint never changes, of course, but all your fingerprint does is unlock the password saved on your Mac.
If you change your password somewhere else (like on a Windows PC, or if an Active Directory admin changes it for you), your Mac won't know about the password change.
The fix is to only change your Mac's password using the Users & Groups preference pane in System Preferences.