Hello! I am also having this issue. My first child between my vampire father/dormant wolf mother was a normal, unbugged vampire. Their second child, currently a toddler, is somehow both a werewolf and vampire. I could not edit the occult in CAS (even on full edit mode) as the sim did not show the occult type menu at all. I do use some mods, mainly Better Build Buy and MCCC. I removed the werewolf trait with MCCC, and also used the remove trait command with testing cheats via vanilla gameplay. Now I do have the occult menu in CAS again (reads as vampire) but the toddler still gets the new fang werewolf buff despite no longer having the werewolf trait. I'm worried this will have more downstream issues as the sim ages up.
The Sims Team