I have an 07 Yukon Denali with the stock head unit. It is the touchscreen NAV Bose system. For a while now, the clock insists on being an hour behind. I can fix it by setting the clock back to the correct hour, but the next time I start up, it changes back. It never looses more than one hour and only happens after I set the time to the correct hour. Anyone else ever had this issue? Is there a quick fix? I've toyed around in the various menus to no avail.