This is usually caused because of hookup wires have been reversed or soldered to the wrong eyelet. This happens when the hot lead wire often white or yellow in color from the pickup is soldered to the eyelet that also connects the beginning of the coil. The ground wire that is most often black in color is connected to the eyelet that also connects the finish of the coil. Because the coil is wound in direct contact with the magnets, the magnets become noisy when touched and similar to touch the end of a guitar cord when plugged into an amplifier.