Ideas
Thanks to every contribution here, I now understand that the main issue (not getting the third trait when aging, nor the reward traits from parenthood) is related to being in highschool when aging while there is a hidden issue with graduation in the game.
I currently see 3 possibilities to avoid this issue without cheats when aging a teenager:
- Graduate early if the teenager has good grades and enough skills to get this possibility
- Drop out of highschool
- Being expelled of highschool
I have used the first option for a very long time without being aware that it prevented my sims to encounter this issue, just because I have tried once to go to graduation event and found it was not worth the time and effort for me.
Today, one of my teenagers was not in a position to graduate early and I got this issue for the first time. I retrieved an old save and tried several things (debug, alternative location for birthday, lifestyle removal, various objects removal...) without any success and ended up in this forum.
It gave me the idea to drop my sim out of highschool which solved the main issue!
My sim got his third trait and his 5 additional reward traits from parenthood, and his parents were able to complete their super parent aspiration.
My sim also got a "No graduation" "reward" trait, and developped two new fears (fear of disappointing his parents and fear of failure).
Of course my sim can still go to the university so it will work out fine for him.
Overall, it kind of fits in his storyline because he got into trouble this same week, got detention and was warned of expulsion possibility down this road...
EA, this is a workaround, not a normal solution, and I wish my sims could get the valedictorian trait. Please solve this issue!