I got the reason why this is happening. When X starts up, it sends a deactivate request to plymouth and not a quit request. So, plymouth keeps running, and it interprets the keypresses of enter and 2 to be of a quit request.
-- Pressing Enter crashes both X and plymouth in graphical mode https://bugs.launchpad.net/bugs/625239 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
