Completing the "Master of Grudges" aspiration (reward from the Lost Legacies event) on a Sim will result in that Sim becoming afflicted by a recurring Bored moodlet ("Never Scared"). This moodlet, according to the description, is supposed to be associated with the Scare Seeker lot trait, but the moodlet will appear regardless of whether or not the lot trait is present.
Update: I've done extensive testing. It's definitely the aspiration itself that's bugged and this is what is causing the bored moodlet issue. The Merciless trait (the reward for completing the aspiration) can be safely added to a Sim using the cheat: traits_equip_trait Merciless. This bypasses having to complete the aspiration and avoids the bug.
Update 2: The bug is worse than I thought. It seems you don't even need to complete the Master of Grudges aspiration to get the bored moodlet bug. Simply having it selected as your Sim's active aspiration will instantly bug your Sim.
This may or may not have something to do with the Master of Grudges aspiration having a blank field where the bonus trait should be. It's a deviance aspiration and therefore should come attatched to the dastardly bonus trait, but the field is empty in CAS. Juliette Monty is therefore bugged from the beginning of any new game since that is her pre-selected aspiration.
