I'm not exactly sure which patch broke this, but it was within the last few months. When I load a household of four young adults, the YA sims' order is different than in CAS, and even giving them all potions of youth in the order they are in CAS will not fix the issue consistently.
For example, I have two married YA sims and two YA siblings unrelated to the married couple. The siblings should be after the married couple as they are younger, but they aren't. In CAS, they are in order: married husband, married wife, male sibling, female sibling, but the order in live mode was at first completely reversed, and now after potions of youth the order is: married husband, male sibling, married wife, female sibling.
It's a small thing overall, but it's rather annoying anyway.
