The story making sense is not a requirement. It's fiction. People write stories that don't make sense all the time and these writers have done so several times already.
So again you are drawing a conclusion or making an assumption that the story must make sense and then making up events off screen to fit your narrative. That's not how a logical argument works.
I take what the story shows at face value. Season 7 is filled with shit that doesn't make sense. The story as told in the show falls off the rails the minute LF hears Bran's comment and does nothing about it.
The writers wanted to excite people. They don't care if something doesn't make sense upon closer inspection so long as it's exciting. We crossed that bridge where excitement or drama trumps plot years ago.
That's just it, you don't! At face value, we are shown scenes with Arya and Sansa in conflict. WE are
NEVER shown scenes to the contrary(until after the matter is resolved). Your the one that has made the argument that it was all a big con job that started taking place soon after Arya came to WF. Regardless of the fact it makes no sense (by your own admission), you stick to it because it fits your narrative of shitty writing. You have no supporting proof of such a behind the scenes scheme (and laughingly have accused me of making up shit that might have happened off screen in the process). And your only proof is generalizations about what and how certain characters should or shouldn't have behaved to support your argument. That,my friend, is the very definition of a weak argument.
If we take at face value the scenes between Sansa and Arya, we are left with the fact they were real, not acting. My depiction of events has always supported just that, what we were shown, taken at face value. Seeing how your the one not taking things at face value, the burden of proof lies with you. Your failing miserably.
The only thing we know for certain is somewhere along the line, Sansa had an epiphany, and FINALLY saw through what LF was doing (Sansa: " I may be a slow learner, but I learn").
Take at face value, that epiphany happens shortly after her last conversation with LF. That is precisely what we were shown, nothing more, nothing less. You can argue until your blue in the face, but you have not provided any credible evidence to the contrary.
So again you are drawing a conclusion or making an assumption that the story must make sense and then making up events off screen to fit your narrative. That's not how a logical argument works.
You can't even make a consistent argument anymore, because you are doing the same dam thing. Your interpretations of how LF should have acted, or what he should have known, etc, don't mean shit, they are just your opinions, and they were not portrayed anywhere throughout the season. And because of this, you say......"shitty writing".
If there is anyone guilty of fan fic, it is you my friend.
The only thing we know for sure is at some point in time, an off the screen conversation between, Arya, Sansa, Bran, and quite possibly Lord Royce did occur. The only scenario which is consistent, if taking the show at face value, is that did not happen until after the Sansa/LF conversation. The only thing you have managed to provide to contradict this is an elaborate series of If's, but's, and most often, nuts.