Unity 5.6 Moving realtime light source, no moving shadows...

I have a swinging real-time light in a room that supposedly casts real-time shadows. There is a radio (static object) near the light, and it casts a shadow from the light, but the shadow does not move at all in accordance with the swinging of the light, it remains stationary. No baked or mixed lighting in the scene, no directional light either, just this one real-time moving light source - why doesn't the shadow move left and right in time with the swinging light?