I think I might have missed the part of the scene after skipping some text, so maybe the dialogue explaining it was there. From what I recall, it seemed like the sister touched Linda and Linda let it happened and wasn't aware that the MC was watching. I could be wrong, though. It felt like Linda might have allowed it, but I can’t say for certain. I’ll take your word for it.
I also want to clarify that I know the sister won’t steal Linda, as I’m aware of how much Siren is focused is on the vanilla love story between Mom & Son. I just wanted to mention this because in other games that claim to avoid certain content, they sometimes include ntr moments between women without the MC knowing.
After talking to her a few times, I didn’t notice much change in the dialogue. It wasn’t a big deal, though—I’ll just move on to another game, like Zombie Retreat 2 or maybe Tower of Passion again, which I really enjoy.
Thanks for your reply, I really appreciate it