For the VOR level sensitivity, it is actually the sensitivity of the microphone. If you set the number to 0, then the microphone sensitivity will be very low, so you need to speak very very loudly to activated the recording. On the contrary, if you set the number to 35, then the microphone sensitivity will be higher, so you can activated recording even with a lower voice.
You set the sensitivity too high, that’s why the quiet noise can trigger the recording. The level sensitivity should be adjust according to your recording environment.