Well, it didnt do the code thing to me this morning, so it may have something to do with cookies on your system, if youre set up to dump cookies on a regular basis, when the cookie is gone the 2 factor shows up, whether youve chosen it or not.

The option for 2 factor authorization is in your Online account options https://accounts.intuit.com/ under Sign in And Security.  If you have that set to OFF, thats the best you can do.