Google is reportedly working on a fix for a strange bug in Android 'Jelly Bean' 4.2 that makes it impossible to set a contact's birthday for December.
The bug affects the Android 4.2 People app, in which the month of December simply does not exist for those entering a calendar 'event' in a contact's details. According to reports, Google is already working on a fix that will be found in a 4.2.1 update.
Android 4.2 is only found on a handful of devices at this point, including Google's Nexus 4 and Galaxy Nexus handsets, and the Nexus 7 tablet.
The version shares its Jelly Bean codename with Android 4.1, and offers only minor differences compared to that iteration, chiefly the addition of 'Gesture Typing' and a 360-degree panorama feature for the camera app.