Can't change name of user in HTTPD settings

Now that I’ve made the heating schedule interface available externally (couldn’t resist and used port 666) I enabled HTTP Basic Auth and set a nice password for admin.
Since that point I seem unable to change the user name or password fields. The page saves and goes back to main page, but the values remain unchanged each time.

I can change the admin name and password fields without any problem, but not user.
The password managed did do something funny and user name ended up starting with a space and being two words, not sure if that’s what’s causing the issue.

Any ideas would be most welcome as it’s a bit tedious.

Did you try to reset the unit?