It's a new rule in FB that "unnatural" MT Moves, that is a non-advance, non-legendary move that can be taught in the games' Move Tutors but isn't allowed to be taught by that particular Pokémon, can actually be still learned in FB.
The only places I think the unnatural MTs can be learned at the moment is at the Move Tutor by paying more ($350 instead of the usual 150$), or the Calendar, when your Pokémon has learned all EM and MTs available for that Pokémon, they can learn an unnatural MT instead or learning an EM or MT (whenever it is when eating the birthday milkshake, or eating the birthday cake while level 99 or 100). So your Bobble, being level 100 and in all technicality has learned all EM and MTs, can learn two unnatural MTs!
As for when, it was talked in the Move Tutor stuff, and then later integrated into the Calendar as a new rule announced
a while ago and added to the first post rules