Legacy Family Trees: Tree collapses/Overlaps/ Wrong connections (1.121.372)

I can confirm that today's patch (1.121.372.1020) hasn't stopped the genealogical apocalypse party!

The 'Unknown Parent' token is being assigned globally to 1st-generation townies and legacy Sims with one listed parent. Because the game assigns the same token ID to everyone, it treats them all as sharing a biological ancestor. So previously unrelated sims in legacy saves are now siblings or half siblings where sims are first generation or have only one listed parent.

Adding parents in CAS doesn't change this because the 'unknown parent' token takes priority. This is presumably the same for players trying to fix it with MCCC.

I have a Sim that was adopted by (the epic) Mitchell Kalani. Mitchell is listed as his biological father. His other parent is 'unknown'.  His married spouse is a first-gen townie, so he doesn't have listed parents. He, too, has an 'unknown' parent. But now, because it's the same token, they're no longer married, and they can't do fun things together because they're listed as related.

If I make another parent for the Kalani Sim - let's say I make a mother - and then try to create two parents for his partner, I can't. I can only create one, because the unknown parent token is absolute. If the game lists the Kalani Sim as having an unknown mother, you'd think if I create a mother for the spouse sim, the game would realise they aren't related. It doesn't. The unknown parent is hermaphrodite and can represent all genders.

I don't see this issue listed in the bug compilations or laundry lists, and since it's possible that this will be a permanent data rewrite on all our legacy saves, can we get an update on whether the dev team is looking at this relationship data specifically, or just the UI layout? Should we leave any precious legacy saves alone for now?