Suddenly, all my soft buttons on SYNC (Audio, Nav, Climate, Settings, etc.) have frozen. They take 20-30 seconds to execute. Navigation has lost its GPS signal. It comes and goes with system resets; works for a few minutes, then frozen again. Dealership reprogrammed and updated to latest version ... even added media hub for CarPlay (which works fine, BTW) but when I picked it up, same problems again with SYNC. I'm taking it back in for hardware diagnostics next.