UPDATE 10:40u: Oplossing die voor mij werkte: app volledig verwijderen van je telefoon en opnieuw downloaden vanuit de App Store of Google Play, dan opnieuw inloggen en meteen handscanner opnieuw instellen
UPDATE 11:45am: The following solution worked for me:
Completely remove bunq app from phone, wiat a few minutes, redownload from App Store or Google Play, then login again as if it's the first time.
Then immediately configure the Passphrase and/or Hand Recognition again.