Yeah this is something I've noticed a fair bit actually. There's almost like a build-up before anything coherent comes through, like the signal is being tuned or something. I've had a few recordings where the static spikes maybe two or three seconds before a response and once you notice it you can't un-notice it.
Not sure if it's interference from the device itself or something external but the pattern feels too consistent to just write off. I've started marking those static bursts on my audio timeline so I can compare them across sessions and honestly the correlation is pretty striking.
Anyone tried recording in a completely shielded environment to rule out EMF interference? Would be curious whether the bursts still show up or if they disappear. Could tell us a lot about what's actually causing them.