OK, My unit has this problem as well. Clock resets to some random time and the audio presets (fade, bass, treble, etc) defaults back to where they were sent. Sounds like lots of folks have had this problem with no clear root cause...
When I checked under the hood for the engine fuses, I noticed that the positive terminal on the battery had some built up baking soda so I took it off, cleaned it and added some dialetric grease
The info on the web and this site is inconclusive... most suggest fiddling with the exteneded service fuse. My pathfinder is a 2011 LE and it DOES have the extended service 10 Amp fuse. I checked the fuse and don't think the fuse is bad but I'll replace it anyway. Its a little tricky to get out - take a pic of the white protective box and you can see where you need to depress the little fingers that hold in in place. If you need to you can release the lower glove box by depressing the sides in and then it will hinge all the way down.
From Nissan:
http://www.nisuv.com/nicont-115.html
If the extended storage switch malfunctions, or if the fuse is open, it is not necessary to replace the switch. In this case, remove the extended storage switch and replace it with a new fuse of the same rating. How to remove the extended storage switch:
1. To remove the extended storage switch, be sure the ignition switch is in the “OFF” or “LOCK” position.
2. Be sure the headlight switch is in the “OFF” position.
3. Remove the fuse box cover.
4. Pinch the storage switch and pull it in the direction illustrated.
Hoping by the end of this I will have something conclusive to contribute. I also need to repair or replace my subwoofer drivers. My teenage son had the car when the bose subwoofer went out... suprise suprise, that seems to be the same time that the head unit started having memory issues as the bass setting is stuck on the 10 setting.