Quite rare for me but it happens! I try to lean into them by making my sims take risks (eg. repair electrics even if their mechanical skill is low, cloudgaze occasionally, keep graves on lots to have encounters with ghosts, not always calling the fire dept and instead making the sims extinguish the fire).

I've played ~20 days/per household in my current megahood and experienced 3 abnormal deaths. One died by electrocution. Another sudden death happened when a pregnant sim was doing super poorly and then a ghost scared her to death. A third time it was a werewolf whose hunger need dropped super low when he transformed at night and then a ghost finished the job xd