I can confirm those detectors are not reliable. I had the same issue of active electrical detected everywhere in some of my walls. After destroying the wall, I can definitely confirm they were false positives. Some suggested this is more common in some types of constructions materials that tend to accumulate charges or something. Like you, touching the wall nearby helped with this. I support others’ advice to try painting a logical pictures of stud position (vertical, all the way up and down, and equally spaced) and plumbing/electrical position according to where switches, lights, taps.