@Chanel1993Do you use any mods? If so, then some outdated mod is responsible for it.
The problem is that even if you now discover what caused it, you can not fix this genealogy anymore.
I can only suggest that you check if all the mods you have are up to date, delete the localthumbcache.package file from the game folder and fix the game in Origin.
This may prevent further such phenomena, but unfortunately, it will not reverse what has already been saved.
I don't work for EA