Quick question: I know you're shooting for the most specific regex, but did you try 'set pre-login-banner enable' on its own with nothing else? Did that at least work for a match?
If not, it might be something even more bizarre. I would recommend at that point having it dump the configuration to a text file and popping it open in something that can show you control characters (gvim's ':show list' command is my personal favorite). I'm wondering if there aren't control characters within those tokens that need be accounted for.