Constant recording of 30 second clips even when Recording Mode is set to During Radar Activity

RCT715, recently purchased, firmware 5.10, using Android app version 3.2.0

Radar is working ok while riding, as I'm getting notifications on the Android app.  But the camera runs all the time, as if it's in Continuous Mode,

My rides are always rural, with approaching cars only appearing many minutes apart.  I would expect a collection of a few dozen videos after a ride but instead I get hundreds of videos of nothing happening behind me.