[NEEDS SAVES] Partnered Sims turn into siblings/family relationships

* I think I found the issue in my game * - The problem shows up AFTER I adopt a kid. 

After going into CAS my married couple becomes siblings. I tried the fix of adding parents but I see that as soon as I get into CAS one of the Sim has already been tagged as an uncle of one of the children (therefore a sibling of his wife). And adding a parent does nothing the issue is still there.

What I would like to add is that since I reverted to older saves, before I adopted the children from my existing family there is no bug. I explain:

- I have a Women single mother of a baby child plus 2 children who are her nephews.

- That Women married a Men from another household created in the save ( not a NPC created by the game ) - the baby is not his

- After I married them I can go in and out of CAS with no issue. ( between them there is no child in the family tree)

- After I adopt one of the kids (through the male Sim, the option doesn´t show up with their aunt) and go into CAS, that's when the family tree gets messed up. 

I tested all of this without mods, but I had mods at some point in the save. I removed them to make all the tests. I'm going to continue to play without adopting any of the nephews or the baby child to see if bug shows up again.