Fantastic Beasts 2: 11 Major Plot Reveals From Comic-Con 2018 Trailer
11. Dumbledore IS Teaching DADA
Confirming a recent point of speculation - after Jude Law said Dumbledore wasn't teaching Transfiguration in this one - we see the future headmaster leading a Defence Against the Dark Arts class, with the students facing a boggart.
It's tempting to see this just as a minor change but, given it's never been mentioned before and comes directly from J.K. Rowling, you'd think there's some reasoning behind it, or at least as to why he goes on to a different subject. Is he merely filling in, or could there be something linked to Grindelwald as to why he can't teach the subject (because of their connection, or because he fears where it might take him)?
It's also here that we see the first signs of Dumbledore's relationship with Newt, and even early on you can see how friendly their relationship is and why he'd be moved to try to defend him from expulsion.