Sentiments Causing Problems

First off, some sentiments pop up for no clear reason. Second, sometimes they just ruin everything they touch. Third, they last way too long.

Today's incident is a perfect example of all of this.

It was a Sim's first day at High School. She had the objective to "Ask Teacher About the Curriculum". On approaching the teacher, she suddenly, for no reason, gained the Suspicious sentiment. At first she became angry, but now in class she's hit with a Sad+2 Gutted Moodlet. On top of this, all her Happy Moodlets plummet at 2-3x their normal time-out speed. It's been 3 in-game days at least, and there is no sign of it even beginning to dissipate. This one sentiment is completely ruining her High School gameplay and there was no reason whatsoever for it to have popped up.