Peanut is in their kitchen line of flavors, it does contain diacetyl, which many vapors choose to stay away from. I don't know if this particular flavor has oil in it like their Ginger flavor does, which is not suitable for vaping.
Peanut Butter from TFA contains acetoin and acetyl proprionyl, according to their website. Also things many vapors choose to stay away from.
With that said, though some do choose to vape them, some of the FA kitchen line flavors are very hard to work with. ULTRA strong, not quite pleasing to the palate.
Hopefully, someone that has much better knowledge about that can chime in. That's all I could find from a quick search.