I just ran into this issue for the first time. Vladdy had a baby with a spellcaster and the infant is ready to age up into a toddler, but I can`t throw a birthday party. I checked if I have this issue without mods (pulled the localthumbcache) and it was the same. I can`t plan a birthday party through the phone or the calender. I thought the child is a spellcaster. It had the spellcaster crib as a newborn, but I checked with cas.fulleditmode and the child is in fact a vampire. I have screenshots attached. I was really looking forward to that birthday party.
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