Yes it's an intentional safety failsafe mechanism. But,here is a procedure that must be performed at every engine startup to by pass this nusiance.
On the Nav.screen, go to menu and press Audio>then press top left corner >then bottom left corner> TWICE. If done corectly, yu will get a service screen. Press and hold the 'OVER RIDE button' until it highlghts and beeps. Touch
No other buttons on this service screen!!!
Now, hit
back button to return.
This will allow yu to adjust destinations while vehicle is in motion.
Bear in mind, once yu shut off the vehicle, it will reset to the normal failsafe mode again.
This info has been posted elswhere.
enjoy