By default, when a one-time password is created for a user, all old one-time passwords for that user will be deleted. This is to ensure that the user can only use one password at a time.
However, in some cases, you may want to allow multiple passwords. This can be done by setting the allow_multiple_passwords option to true in the one-time-passwords file.
When this is true, old one-time passwords will not be deleted when a new one is created.