Mine does the same thing, especially when the weather is cool. Once in a while it does it a shutdown also. I dunno about battery voltage (measured about 12.95). It sure acts like a problem with the ignition switch, but can't tell for sure at this point.
2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg
And remember folks, Only You Can Prevent Hilliary.