I think you’re not quite up to date.
I did enter 2 passwords (user, root) and they are not the same.
The GUI started without password, But none of these passwords worked in the installed system
(this is no passwordless installation, but only a passwordless login)
It’s the latest ISO for XFCE.
Yes i could, But
No, unfortunately I can’t do that anymore,
as I reinstalled immediately afterward without checking the relevant box. (I’m currently reinstalling my system, not troubleshooting Calamares in general.)
Nevertheless, this reminded me of some threads in the forum where people had similar problems right after reinstalling.
In those cases, every “expert” (myself included) assumed the user had made the mistake.
Since it happened to me too, I think that back then, the user wasn’t actually making the mistake, but rather that they simply encountered a bug in Calamares. But if no one believes it’s a bug, it won’t get fixed 
Please excuse my bluntness:
Unfortunately, at that moment, you don’t have any concrete proof. And neither the time nor the inclination to prove to the programmer that there’s a bug,( and possibly even to show them exactly where it is). After all, you just want to complete the installation successfully.
## No proof
But an indication that it is indeed a bug 
