Also try cleaning the front of the car, near the frunk. There may be some debris interfering with the sensors.
Rebooting the displays may help too. Hold down the two top buttons to the left and right on the steering wheel for 10-20 seconds. After that reboot completes, press and hold the two scroll center buttons to the left and right on the steering wheel for 10-20 seconds.
we had the same problem today (for the second time) on our Model X. I discovered that when I toggled with the volume control, the sound suddenly disappeared (even after increasing the volume again). Hope this works next time.