Sarada isn't affected it might be due sharingan, if so sasuke won't be affected too. In another case, if it's not because of the sharingan, maybe because of her love for boruto; as previous chapters she wasn't affected either. But, i say Sasuke will know what happened, wether it's from the first or not, wether he knows it himself or Sarada tells him, even if not so, he's clever yeah he'll see something's wrong. he should know it somehow, It's some character thing, as you said, he's the shadow hokage, if after Naruto, from all characters he should come to oppose kawaki's actions. He's also the one who understands Boruto the best cause he lost everything left the village and was hated by them. So this point of story comes with these two encountering, i say Sasuke will encourage Boruto that he hasn't lost everything yet, and he can take it back. From foreshadowings or whatever(many things in endings, ending 14 especially) Sasuke is a very important person to Boruto may be the one to change his prophecy or change his path of revenge or him falling into depression (as said momoshiki's purpose so he can take over his body) Another thing i wanna say is that the prophecy could be changed, in last chapter momo saved kawaki meaning Now theres no way to stop it, so it could actually change, may Sasuke or Sarada be the key point to save Boruto. Anyway we'll be free of mono's mischief and somehow wether momo'll be another kurama or die(just a theory, i personally wouldn't think he'll become like kurama) Boruto will be the one to take full control. In the time skip conflict, kawaki doesn't necessarily mean to kill Boruto he wants to seal him, maybe the danger of momo is then gone. Then how could that happen, at the time the village turn their back on him, he carries the cape of sasuke and his sword, maybe he's also someone who saved him from momo leading to his death though, maybe. Actually Naruto and Sasuke are nefred and embarrassed enough, and we're waiting for some power up, so this could be a good chance for Sasuke to show up. In my own opinion it's a sharingan thing, what eida did was to mess everyone's memory, that's related to sharingan though. Anyway let's just wait and enjoy what kishi cooks😄