12 days ago there was as "Facebook is nearing a reputational point of no return" ( https://news.ycombinator.com/item?id=28786250 ), so maybe it's some kind of "better change before it gets worse"
It's important to say that BURP only deals with http like requests ( http/https websockets ) and the app can be sending/receiving data via other protocols, the same way you can't see whatsapp messages via burp [0]
https://news.ycombinator.com/item?id=41406367