I had this problem, too.
The "charming lady" in my nav just wouldnīt stop talking to me, until I reached a chosen destination.
After many tries in vain, I found out, I had to say "Cancel".
Then I saw a menu where I had to say "Stop guidance" or "One",
because that was the first command in this menu.
Then, finally, there was celestial peace.
The only problem left is, I canīt stop her talking while in a phone call via HFT.
At least, I donīt know how, so far.
Ok, that wouldnīt make sense, anyway, I guess.
If you stop the guidance while in a call you might miss a turning or so.