I'm watching the scene with Lady Olenna and Jamie. As he is getting the wine, Olenna says, "your brother and his queen thought you'd be protecting Casterly Rock." Jamie kept rambling on but the point is of her words. Tyrion and Dany have made no mention of High Garden that I can recall. Vary's didn't make mention of High Garden. Who was communicating with Olenna from the Tyrion/Dany faction? If it is Vary's, he's the one not helping Dany's faction but spying on her.
Those words by Olenna, I think, was a small one liner that will mean something later.