Hey I had a CAS created vampire and CAS created mermaid have 4 kids, no multiples. All were hybrids although I've used cheats to make two one or the other as once they became teenagers glitches started happening (mainly legs disappearing, getting stuck in the swimming animation, changing clothes for dark form/mermaid form and then not being able to change into another outfit, and getting stuck hopping around with a tail instead of legs after removing the vampire trait through the in-game cure). I was going to take off both traits on the daughter to make her a spellcaster but also plan to see if this happens naturally again by putting the two teenagers with spellcasters and see what happens with their kids (ones a mermaid-vampire hybrid, the other started as a hybrid, started glitching after using the vampire cure so I used cheats to remove and then reapply the mermaid trait). I'm able to revert the full hybrid back to normal when he shows his dark form, the issue seems to be with the system trying to sort out a mermaid tail. Same thing happened with the vampire-cured hybrid, no legs when he got in the bath but then I was able to give him a tail through CAS (since now he was just a mermaid), but that caused the hopping around on his tail. To note, I only have one piece of custom content (a shelf for placing objects) and this started before I added it to my game.
I think I've attached the right saves, it should be for the Saldana family (Mom (vampire), dad (mermaid), 2 teenage sons, 1 child son, 1 child daughter, 1 cat). One should be before I tried to fix things by doing the factory reset, and the other should be after when I used cheats (factory reset didn't work). I have laundry day, vampires, strangerville, seasons, island living, pets, backyard stuff pack and realm of magic (children were all born before the realm of magic pack was released). Let me know if you need anything else.
Pre Factory Reset: https://drive.google.com/open?id=1RP3M7dFm-Az0T4Y8afxF1mX7qQYu2MR2
Post Factory Reset and Cheat Editing: https://drive.google.com/open?id=19xN-Q1KMDPL8_uT59eN-a5YNTUdrYzgF
