Legacy Family Trees: Tree collapses/Overlaps/ Wrong connections (1.121.361)

After the release of the new expansion, I decided to try merging the Laurent family with Fabrizio Capuleti (I wanted to do this either using a developer cheat or the new board). I've been playing this save for a long time, so after the update that changed family trees in old households, there were no changes. But it came as a big surprise to me that the Laurent family tree is broken. In short — Arnesse Tibi now has a hidden son, and she supposedly gave birth to Hector Laurent through him. I don't know how to fix this, and I doubt it can be done using a developer cheat.