SYNC-Bluetooth Audio 'jumbled' on car start
Generally when a vehicle cranks the engine there is a lot of stress on the electrical system, in some cases the power supply to ECUs, such as the SYNC module or the ACM can go below the minimum required for them to function, so straight after a crank they can be doing a lot of initialising processes at the same time as trying to play your audio.

I'm sure that the SYNC module uses a 400MHz processor, which isn't really that powerful compared to modules that other automotive manufacturers are using.