If your login server system has a directly attached character display serving as a console, you may also want to set display_terminal_device to none to disable Command Line Login on the bitmap display login screen.
Alternatively, if a command-line login (getty) is running on both the character display console and the bitmap display, you can change display_terminal_device to the command line login (getty) device on the bitmap display.
For example, if the bitmap display command-line login (getty) is on device /dev/tty01, change the display_type to local@tty01.