Family Tree/Relationships completely broken after saving and reloading

Hi everyone, I really need some help with a persistent issue.

I created the entire Goth, Crumplebottom, and Bachelor families/households. I used both CAS and MCCC (MC Command Center) to set up the relationships between them correctly.

The problem is, every time I save the game and quit, the family tree relationships get corrupted when I reload the save.

For example:

- Mortimer's parents turn into "Unknown Sims."

- Cornelia and Gunther (who should be his parents) are listed as his Aunt and Uncle.

- The entire genealogy is completely messed up.

I have deleted the households and recreated them four times already. Every time I finish setting them up, the family tree looks perfect in-game. But as soon as I save, exit, and reload, it breaks again.

Has anyone experienced this or knows how to fix it?