Witches are bound to turn against their friends at some point. Look at Damara, she turned against her team mates and sabotaged their session. As for Jade, she went Grimbark because of the Condesce and turned her friends, especially John and Roxy

Feferi didn’t exactly turn against her friends. But she did get more Eldritch. Witches ARE at risk of losing themselves to their Familiars, to their Aspect. So if their ‘losing themselves’ correlates to turning against their mates, yeah that could happen.