Lily Zhu mysteriously died. Anyone encountered the same?

Game Pack - Moonwood Mill

I was playing that immortal werewolf Lily Zhu with her offsprings and intend for her to live forever. I unclicked the 'Play Household' for 1 day to played some other households. Today I just found out Lily Zhu is dead!! In the family genealogy chart, it shows that she died of old age (How is that possible?). Did she herself remove the immortal trait with autonomy on?

Please share if anyone knows, many thanks!!!!!