Someone may correct me here, but I would’ve expected that to be normal, as on my 32 classic, my keel is earthed via a huge flat cable, and I believe this goes to an area where the mains earth is also connected, and therefore the negative of the battery too.
If the mast shrouds connect through the hull to metal supports that are also connected to a common earth point, then in turn the mast may well also be connected.
Then of course there is the metal post (sorry if it’s got an official term) that the masts contacts with that also contacts the keel possibly?
Be interesting to know if this is a correct assumption or not 🙂