To Update this thread... still not sure if this is a bug in kix or not. Running whoami always returns System. Sent an email to Ruud, awaiting his response.

Using Kix 4.66,
@userid =
on Windows 7 =System
on Windows 8.1=Computername$
on Windows 10 =Computername$

To address these inconsistencies...

 Code:
function System()
  if @userid="System"
    $System=@userid
  else
    $System=@wksta + "$"
  endif
endfunction