Oh, I don't mean to suggest it's super-secret knowledge, just that evidently Trouble knows enough about vampires to call them something other than simply "vampires". Same if they'd said "Kindred". Of course, yeah, if they've been investigating a Sabbat sect then that knowledge itself probably counts as a masquerade violation, not a reason to not bother enforcing the masquerade with them.It's worth noting that, while specifics regarding the fate of each antediluvian and whatnot is deep lore, the general myth of Caine and use of the term "Cainite" is common knowledge among the Sabbat. It's the term they prefer for vampires, and they often call their sect "the Sword of Caine." And even the Camarilla doesn't suppress that knowledge so much as they promote skepticism towards it