Sims are getting culled

I am currently on my 4th generations of my save and I have been having this issue recently. The kids of my sims siblings are getting deleted. I only noticed because I have them interacting a lot so I don’t know if this is happening with other sims too. I have the maximum sim count set to unlimited, the households are moved into “my household” and I even flagged them using MCCC to never cull. Also I have the “bypass sim culling” setting from MCCC enabled. At this point I don’t know what to do to prevent them from disappearing and it frustrates me a lot. Moreover, I have a save in which I played for 11 generations and this problem never occurred.