I do think that leaving LiHuan behind was kinda rude and out of character on YuYang part, but I also think he's doing it on purpose. Let's remember not long ago he was panicking people might misunderstand his friendship with LiHuan for romantic interest, and he doesn't want that. I believe he's trying to show everyone (including LiHuan) he doesn't particularly favour him over his other friends, therefore he puts some distance between them by acting this way
I do think that leaving LiHuan behind was kinda rude and out of character on YuYang part, but I also think he's doing it on purpose. Let's remember not long ago he was panicking people might misunderstand his friendship with LiHuan for romantic interest, and he doesn't want that. I believe he's trying to show everyone (including LiHuan) he doesn't particularly favour him over his other friends, therefore he puts some distance between them by acting this way