Lightning sensor too many disturber detection problem

Hello,

We encountered a problem whereby the AS3935 sensor was behaving normally when it was first put together, even producing the correct “lightning detected” message when we used a lighter ignition to imitate the lightning phenomenon ( as suggested in a guide : ). But after a while without any particular change to the set-up or environment, it starts to produce “disturber discovered” message constantly, which do not change even if we ignited a lighter right next to it. 

The sensor even spit put “disturber” when we just put our hand next to it when we use the default settings. 

Then I played around the few noise-related parameters, and the best result I could get is with sensor.set_noise_floor_lv1 to 7 and sensor.set_watchdog_threshold to 6. With these numbers the sensor detect any close electronic objects as disturber, but still we cannot replicate the lightning detected effect with a lighter anymore. 

My questions are: 1. what could be the reason that AS3935 changed its behaviors from detecting the “fake” lightning to outputing disturber constantly, and 2. What can we do to adjust the software to hopefully restoring the correct sensitivity? 3. Is there any other way to test it's working properly other than waiting for a storm?