Unfortunately is is happening :( I've never come across an Incest setting in MCCC, so I definitely didn't turn anything on in there, and I don't have any other mods that have that feature. And like I said, even when I removed all of them, MCCC included, and left nothing but Wonderful Whims in, her brother was still being flagged as Extremely Attractive. Is it possible that the mod simply isn't registering/reading their sibling relationship correctly?