During sound routine maintenance I noticed the shielding for the P leads on both of my slick mags isn’t grounded. Magnetos are still a bit of a magical box for me but my understanding was the shielding is supposed to be grounded at the mag side and floating at the switch. Is this correct and if so is the fix as simple as stripping back some sheath exposing the shielding then adding a ground strap to the ground screw next to the p lead on the mag?