Working save: Genius, Bookworm, Loner, Speed Reader, Storm Chaser, Night Owl, Morning Sim, Handy, Independent, Steel Bladder, Gym Rat, Professorial, Savant, Seldom Sleepy, Quick Learner (I'm not sure if it triggered right at 12 or not, I didn't pay that much attention)
Not working: Creative, Slob, Childish, Mentor, Night Owl, Morning Sim, Storm Chaser Sim, Angler's Tranquility, Hardly Hungry, Marketable, Role Model, Death By Old Age, Domestic
Something to add. I've been playing with a different family on the same save and a few of them also had 12 or more traits by the time I was done with them without triggering it. Then, last night, I moved that family in with my original sim through manage households. I went in to play and as soon as the house loaded with the combined family, the achievement triggered. So I have no idea what is going on there, but I have the achievement now??? I don't know if moving the original out and back in would have done it because until that point I hadn't moved any of them after having 12 traits (but in the first save where it worked I had never moved her).
Having this same issue, and I was wondering if DLC traits could be the problem?
