So I don't know if this is related to the vampires pack (possibly lot traits?) or just a random bug, but I have a vanishing baby. Here's what happened:
My vampire couple had twins, somewhat to my surprise. I named baby C first, and her bassinet appeared in the expected place, right in front of the laboring mother. I named baby D when prompted, and her bassinet showed up a few yards away. All seemed normal until I decided to age up the babies.
I happened to be by baby D, so I did her first. Everything was normal, I had a toddler. I sent my mother to baby C's bassinet, and...no animation, no sound, nothing, just a suddenly empty bassinet, no toddler, and all the family portraits at the bottom of the screen unchanged--male vampire, female vampire, un-aged infant, toddler. I tried to reset baby C and was told "that sim cannot be found" or some message to that effect.
I re-loaded an earlier save and went through the whole thing again, this time aging baby C first--and once again, baby C vanished. I went ahead and tried to age baby D, as well, and SHE vanished. I've tried a few variations on the theme, and basically if I age baby D first, I can get one toddler, toddler D. Otherwise, I get zero toddlers. Baby C will not age to toddler, and only vanishes.
I have the "On a Dark Ley Line" lot trait, and tried a few different "try for baby" options before taking a pregnancy test, so I'm not sure which one actually caused the pregnancy.
