3DS randomly resets date/time?

My 3DS randomly set the date and time to 1/1/11. I noticed this when i went on to play New Leaf just now. Anyone else have this problem? I have the red 3ds from the super mario 3d land bundle.

This happened to me before, so it could be the same issue, or something completely different.
Basically, for me, the battery was loose/faulty. Tapping on the back of the console in certain areas when it was turned on would turn the console off (because the battery was loose and would unplug itself), and the next time I turned it on the console would be at the 1/1/11, 00:00 date/time. So if you want to find out if this is the issue, basically turn your 3DS on, and then tap the back on the console in random spots, and then like tap the corners and sides on your desk or something, if it turns off, then that's your issue.

To fix it, unscrewing the back and pulling the battery out and putting it back in again helps, but it's only a temporary fix. If you want it properly fixed you need to send it to Nintendo.

My New Leaf game did this once (don't know about the 3Ds) but it reset to 1/1/12 instead.

This happens to my brother's 3DS, as well, but Jake actually helped it fix!