I think this is part of the same issue but am open to being corrected on that, and will open it as a new report if need be.
Despite knowing that cloning is super-buggy, I did it anyway in my sprawling family save where the genealogy is very important to me. Er. Because when my scientist unlocked it I was all but hyperventilating with glee--"OMG YES Zachary needs a twin! the only thing that could be better than one Zachary is TWO ZACHARYS I LOVE HIM SO MUCH!!!"--that's why. The only reason I didn't do it on the spot was bed logistics at home, LOL. He lives with his wife, his two moms, his sister, and now his baby. I heard about the bugs and dithered for a very long time, but finally temptation got the better of me. I figured I would clone him and move him, his wife, and his baby out immediately to prevent the married Sims become siblings bug my friend has struggled with.
Cloned my scientist. He and his wife aren't siblings, his moms aren't siblings. Hooray! Moved my scientist out with his wife and child. Edited the clone in CAS. His mothers are still married and not siblings! Hooray!
And then I noticed that one of his mothers' genealogy was screwed up and was suddenly the child of her father and her father. She still had "relationship bits" with her mother that showed up in the profile panel but not in the genealogy. I tried to edit the relationship in MCCC but only sister and daughter were available, possibly because of the "mother" relationship bit still being there? or maybe because on some level the game still knows that's her mother but it can't display it properly? Or is it because she already has two fathers? I don't know, it just didn't work.
Broken:
But also:
I managed to roll back to a point before this happened (because I knew it was risky and stored extra saves from before), and only lost the house reno from when my scientist moved out (which tbh I could load the house into my personal gallery and replace the lot they moved into, and might, or I might just say screw it and do it over), but... I think that yes, it's the same problem because cloning seems to corrupt the family tree in weird ways. Well. I also lost the clone because I had to roll back to before the cloning happened to get his "mother's" genealogy to not be corrupted.
Rolled back:
I'm really disappointed that one of the crowning rewards for being a scientist is apparently too risky to do with anything but a single Sim living alone with no spouse or family.
