Sorry, only thing I can suggest is getting the Nav/ICE system onto a diagnostic, as I would assume one of the many computers for the system (heck the 2003 has one for the Radio, one for the Telly, one for the DSP, one for the Sat Nav and one for the other things so the 2006+ model with touch screen and reverseing cameras must have a few more.....) must have lost it's marbles.....
Check in the rear lefthand quarter where all the system ECU's are located and check for any condensation build up, the weather is changing making it more susceptable for condense forming, maybe there is moisture in one of the connecters, or units.....
There is a common problem with the earlier L322's with moisture getting into the this vunerable area....not sure if it was sorted by 2006, but take a gander in anycase....