Creatures Caves

So I have a norn who grew up normally, had babies normally and at 7 hours old, her life force, which had been steady at 77%, started decreasing. She was marked as dead in the observation kit, and her life force is at zero, and she is still walking around and able to breed. I have never had a norn behave like this before ever. She is a descendant of Smaragdina (the pigment bleed green norn) and Paul (eclectus parrot norn)

I had been noticing some mutations with her brothers and sisters... for example three of her siblings inherited their mother's need to die as soon as the wind blows. I've literally had to raise them in the world by themselves. If another norn even walks by them they die. Their mother was a challenge to breed because of this. Another sibling who was male could continue to breed well into the 20 and 30 hour mark and became fertile with a high drive the moment he became an adult. He behaved similar to an essex norn in that regard.

I've just never had a norn die but still be alive lol. Has anyone else experienced this with any of Smaragdina's offspring? In the past few months I've hatched close to 300 norns and I've been playing Creatures since I was a kid in the 90's and this is definitely a first for me.