Preventing your device from vibrating whenever it gains or loses its mobile network connection

I've been using a Moto G (2nd generation) running Android 6.0 "Marshmallow". I was playing with the settings, and changed some setting. Now, every time the phone loses or regains cellular service — for example, when I'm in the basement, or when I enable or disable airplane mode — the phone vibrates two or three times. The vibration is noisy and annoying. What can I do to prevent it from happening?