Vampires or Casters?

Lina has all the perks a caster can purchase, and she is still knocking her household out with potion backfires. I'd say it's 50/50 regarding success. I notice her failure rate is higher on the more difficult potions than on the easier ones. She rarely fails at making a rejuvenation potion, for instance, but the immortality or youth potion will backfire at least 50% of the time. It's possible it's just buggy because they're still gathering information on what needs to be fixed, and that this abysmal failure rate my sim is experiencing has more to do with bugs and less to do with her pure human lineage. I am curious to see how her children with the weak bloodline trait progress through their own study of alchemy once they are of age, though.