Bug:
Reincarnation pop up claims that the Harmonized Settlement start begins at Age 30, Setting menu says Age 24, the second one is right.
Viewing post in Cycle of the First Dawn comments
It's misleading, anyway, but there's definitely some sort of effect where enough progress makes us not lose quite so much time as the 30-year-old default age for the Harmonized start. I don't think it's a bug, it's just a label that hasn't been updated yet. I'm not so advanced, so my Harmonized start is at age 29 instead of 30.