Yeah this happens on pretty much every session I do worth mentioning. The static burst is almost like a carrier wave or something, the signal getting tuned in before the voice can push through. I've started treating it as a cue to actually pay attention because whenever I catch that burst and then go quiet, thats usually when you get the clearest responses.
Had a session up at Chatsworth area last autumn and it was doing it repeatedly, burst then response, burst then response, almost rhythmic. Ended up being one of the better recordings I've got.
Curious whether anyone's tried boosting sensitivity right at the moment of the burst or does that just introduce more noise? I've experimented a bit but not sure I'm getting better results. Might be worth tracking how long the burst lasts before the response comes through, see if theres a pattern across different locations.