My understanding is that the first attempt is creating/enabling the root account with a blank password and that the subsequent login is actually utilizing it (which is kind of bizarre and probably why this was missed in testing).
The first time I tried it, it just worked. I'm certain I've used root before. On the GUI portion it works with no password, but on the terminal it does not let me login as root without a password. Some weird OS magic must be going on there?
AFAIK usually sudo doesn't let you enter an empty string as a password, even when the actual password is empty. So that is what you might be experiencing.
it worked for me on 6th try or so. First few times, the prompt was returning to my user name, but then another failed attempt left it at 'root', and the next attempt succeeded
root IS an admin in macOS. You just cannot use root the same way you expect root to work in other Unix OS' without changing stuff in the BIOS (or whatever it's called for Apple) but you can still do most admin things with root. However root does get admin privileges, but when it comes to some system directories he is banned till you "fix" root privileges.
