I am having a similar issue. I and my two kids all started villages at the same time. I'll call them A, B and C. Village A has never been sustainable, and never got more than half the puzzles done before everyone dies off. Villages B and C both have all the puzzles solved, and 90 villagers. We have restarted village A 4 or 5 times. The most recent time, everything seemed to be fine, then 2 hours later (on 2X speed) all dead but one 6 year old. I also noticed my adept farmer didn't seem to be keeping up with the fishing, so the food was always low. Why does this one village have so much trouble, when we had no trouble at all with the other two?