I got this too with Creative. I didn't mind as much though, as I simply changed traits to a Sim I made myself - I did initially choose the Creative trait for a reason, I just found another one I liked better, so I don't mind him "Feeling uncreative" sometimes as it still fits his character.
I think it applies to the negative (tense) buffs that come with (some) emotional traits. I've also changed traits like Childish and Self-Assured and in those cases they were just gone for good. The tense moodlets that come with Active, Creative, Genius, Romantic, and I'm probably forgetting some here - but those emotional traits. Those will linger.
I don't know an actual fix for this, but you can use cheats to remove these buffs when they come up.