Openfire 4.4.2 setup with external MySQL DB

Hi I have tried to setup Openfire 4.4.2 with a clean MySQL db. Unfourtunatly it is not possible to set a custom admin password when asked for it. It tells me that the default password is wrong. If I skip this step I cannot login with the default credentials.
In the end I rerun the setup using the internal database and I saw that the dialog for setting the custom admin password is different. I does not ask for the actual (default) password. And this works. Is this a bug in the setup script?

Best regards,

What operating system?

Debian 9