It is quite mind boggling, but somehow Google missed the fact that there are 12 months a year in the People/Contacts app of Android 4.2. This only affects you if you are trying to add a birthday to a contact and it happens to be in December. The choices go from Nov straight to Jan when trying to pick your date.
Our friends over at AndroidPolice have verified the bug, and that it has been submitted to the Google team (bug 39692)
And of course, funny comments ensued. My favorite was this one
Source: NexusTablets via AndroidPoliceOriginally Posted by Swapnil Chitnis