Why does my V40 play the notification sound and ringtone when a call comes in?

[Android Central Question]

After my Verizon V40 updated to Pie I did a factory reset. Whenever a call comes in, it starts playing the ringtone, but a notification plays every few seconds as well. I can find no setting or option to turn such a feature on/off. And have never had a phone behave that way. I ended up having to get a warranty replacement for a hardware problem, but the new device does the same thing.
I use Nova launcher and the stock dialer.