iPad iPad 4 Keeps Asking For Newtwork Password Even In Auto Connect Mode

Whether it's the iPad 4 being powered off or reconnecting to my home WiFi router (after using a free WiFi hotspot) , I have to reenter the home network password. I've tested my network with a friends iPad 2 and an old iPad 1, and they do not require the password. All 3 are set to automatically connect, but it's just the iPad 4 that keeps asking for the password.

Is this a bug inherent to the 4th gen iPads?