sim who doesn't have erratic trait, gets a moodlet only erratic sims can get

i'm playing a legacy and my sim married salim benali (one of the townies in the art district from the city living pack) and he got struck by lighting after coming back home from work. soon after he got a positive moodlet and underneath the main text it said: from erratic trait. keep in mind, salim doesn't have the erratic trait. not sure if this is considered a bug, but posted it here anyway.