I stumbled about this question when it was eight hours old.
A new user (not the question author) commented under the question. The reputation score of the new user is "one". Looking immediately at the user profile I see an
(unregistered) beside the user name, also the user has not posted any questions or answers yet, so it is unlikely that the user had at least 50 reputation points when he posted the comment.
How can that be possible?