Splash screen shows on a cold-boot only. A cold boot occurs after a nav has completely shut down, which occurs 60s after the last door has been closed and the car locked.
If the nav has not completely shut down, then it starts in warm-start mode, and no splash screen is displayed.

Try it as follows: open boot, observe red light on nav. Close eveyrthing else and lock the car with the boot lid open. start a stop watch when you lock the car. Observe how the red 'activity' LED goes off after 60s. The nav has now totally shut down.

Now unlock the car, and open the drivers door. Do not yet put the key in the ignition. Observe how the splashscreen appears until you turn the key on. Splashscreen indicates cold boot mode.

Jochen