Lately I've noticed that my Sim kids seem to have a problem with aging. I play lifespan long, with aging and story progression on, and the kids don't seem to have their birthdays until I switch back to their household. For example, when I leave a household, the Sim kid is a toddler. His avatar never updates and so I keep thinking he's still a toddler. When I switch back to his household, he's a child and it looks like he JUST turned into a child because he isn't any further into childhood according to his "age." Then that night, he has a birthday and jumps to being a teen.
This has happened now three or four times with different Sim kids. I also think (although I don't quite remember) that one of my young adults aged up to being an elder, skipping the adult phase entirely.
What gives? Why aren't the Sims aging along with story progression? Also one poor kid who went from child to teen apparently never went to school, met anyone, or made friends. His only relationships are his mom and dad.
I am CC free (minus stuff downloaded directly from the EA store, but not the exchange), and have no mods.