2 metres is a remarkable range !! Is that 'front end' a low-pass filter ?
I ask as I use a budget commercial 'volt wand', often have to do some waving and back-tracking to figure which of several adjacent wires is which.
One head-scratcher was due to tracking in a damp attic, so that if adjacent room's lights were on, a room's LED lamps would blink every 10~20 secs though switched off. Although the creepage did not give a shock hazard, *all* the wiring tested live with the volt wand. Poking in a 'neon' tester told a different story.
FWIW, improving the ventilation resolved the problem...