This is a non-ubuntu bug: it's bug in a custom GDM theme*, if any action is to be taken, it would be a report to the theme author (whom we don't know, so no action can be taken).
* Many GDM themes do this, since their creator designs them at a high resolution, before the user installs them for use at a lower resolution, which obscures the text feedback. -- Login screen does not fit https://launchpad.net/bugs/56054 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
