One other point. If the slats and flaps are in effect ungrounded (unearthed for the English speakers) there could be another situation and that is the development of streamers. These are electrical charges that can arc from and ungrounded system or even a small component and the charge can be sufficiently strong to blow a hole in the aircraft in trying to connect with an attached lightning strike. This happens a lot on composite structure that is not bonded to the structure. It also happens a lot on Radomes on the nose of the aircraft.
Airbus aircraft have diverter strips on the Radome so this is not a problem. At least on the nose. And, the flaps and slats are composite.
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The Cat