Why does my car radio only echo on the NPR stations?

When I have any of our local NPR stations on in the car, there is a random echo of the last two or three words spoken by anyone. When I say random, I mean exactly that. I can’t figure out any specific timing, or any type of voice, nor is it specific to a show or broadcast. It happens with both live broadcasts and taped shows. This does not happen with music, only when someone speaks.

The stations are 90.3, 89.7, and 104.9. The last is our classical station and is part of the NPR local NPR group.

The car is a 2014 Ford Fusion.

This does not happen with any other stations.