[ARCHIVED] (Group) Conversation leads to inappropriate love interest

Product: The Sims 4
Platform:PC
Which language are you playing the game in? English
How often does the bug occur? Rarely (0% - 9%)
What is your current game version number? 1.92.145.1030
What expansions, game packs, and stuff packs do you have installed? I have every pack except luxury party, batuu, wedding stories, and high school years I believe.
Steps: How can we find the bug ourselves? I don't know, I was checking one of my sim's relationship panels and noticed that he had romance with his brother. I assume they gained romance through an autonomous interaction, perhaps in a group conversation? The romance interaction panel remains unavailable between the two so I know I didn't do this on accident.
What happens when the bug occurs? Related sims gain romance with each other
What do you expect to see? No romance between brothers.
Have you installed any customization with the game, e.g. Custom Content or Mods? Not now. I've removed them.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure 

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I was checking the romantic relationship panel of one of my sims and noticed he had a small amount of romance with his brother. I don't know when this happened except that it maybe happened today since I didn't notice it yesterday. The romantic interaction panel remains unavailable so I didn't do this on accident or on purpose myself. My personal theory is that they autonomously interacted in a romantic way? I have the Free Love NAP in play as well if that might be a contributing factor. They've both been in group interactions with other sims while flirty as well, so it might have come from that?

Yeah they're undertale characters. But anyways. This is a really weird bug that made me immediately kind of upset because I have PTSD, I hope my information can help you find where it came from and how to turn it off.

EDIT: The version number might not be correct, I use the origin launcher and can't look at my game on there, it's the most recent update to the game though, I know that, since I updated it a few days ago.