dying when sims come cheerful

So very time my sims becomes cheerful within minutes they die and I can't bring them back can we fix this. It's really early in game too, like i just started the wagon train comes in with the fruit cake they start laughing after becoming cheerful and won't stop than they die that gets really annoying. it's been going on for a while and I noticed no one addressed this i guess they think it's normal but i do not think it is because it has never done this before it started after i got the like and death expansion but it's really getting annoying and I do not want to have to keep restarting a new game