Hi Edward
Life has been much busier this year than I anticipated. I had hoped to already have released the nighlies as the next version, but haven't had much time at all.
Computer account authentication should happen at DHCP time. They should never see the logins screens, so not sure why you think it's taking longer for them to login.
You can turn on some debugging in Freeradius to get an idea of what is happening, but unless you can sit with a computer having problems, and the server at the same time, debuging can be hard. Ideally you want to see the failure scroll past and immediately stop the debugging so you can see what the error was.
I had noticed the occasional error with logins, but haven't been able to work it out yet either. I'm wondering if it's actually an AJAX "double call" in the login. Might need to do some client side debugging too.
Regards
Tim