News would be travelling across the narrow sea. Possibly instigated by Varys, as it’s in their interest. You’d think there’d be rumours flying, which Cersei and Jon are just confirming.
Yes I know but when you establish a reality or a cultural mindset (even in a fantasy setting) you need to acknowledge a shift in that reality. I could be wrong, I could be forgetting some scenes but it seems like lazy or neglectful that everyone has gone from being sceptical about everything to just accepting everything.
How had Arya managed to not hear about the Battle of the Bastards until pie boy told her?
Not the first time Pie Face McGuffin has facilitated the spread of news.