setup-user with -f and passing an existing username loops forever

/ # setup-user -f testuser
Setup a user? (enter a lower-case loginname, or 'no') [testuser] 
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use

/ # setup-user -f xyz
Setup a user? (enter a lower-case loginname, or 'no') [xyz] testuser
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use
adduser: user 'testuser' in use

this is because it then skips the fullname ask, and the interactive ask, but does fail repeatedly anyway in the adduser part, and loops forever