I had a similar problem at log in. what I found it was my key board.
I had for got that it would work fine in windows and mac, but not in Linux or BSD.
By trial and error, I found that using the enter key on the numeric pad did work.
That is it.
I purchased a new key board for gaming, but some of the mapping is different cussing all problems.
I downloaded the ISO 4 times, it was not the ISO but the mapping on this keyboard.
Also at log had to hi light mate as default, the user ultimate and them enter as the password no upper case letters.
It has been the fastest boot, also the first time that I can use my HDMI port as default video display.
Without having to change display ports makes it simple.
having 4 other components connected to 1 monitor and not having KV switch in the makes it simpler.
Thank you for all your work, and take care TheeMahn.