Sims only die of old age on restart of the game not while game is in progress

Similar but not quite same issue. Teenage Sim died on opening game earlier this week. Didn't seem to be an obvious reason for death, but was angry from mood swing. On closing game previously I had moved 1 young adult out of the family. I quit without saving and on relaunch had no issues. The day after I got the 134 error, which may be connected, and has prevented me from knowing if it could be an ongoing issue.

I'm playing on a macbook pro, have only family and city living expansions and no mods.