I can see that from your screenshots. I also see the household includes a pet, and I suppose it's possible the challenge got assigned to the pet, instead of the Sim, if they were both created in CAS when you started the scenario. (Stupid, I know, and it's just speculation) The scenario should still finish once your household reaches 400,000 simoleons or you could just cancel it.
Whatever went wrong, I don't think there's any way to fix it, so I would suggest just starting over. It looks like you are still fairly early in the scenario, and you won't get the full experience if your Sim is earning skills.
The scenario doesn’t allow you to create more than one Sim. The pet was added later.
