Winged morosa demons

I like these demons a lot. They shoot chain lightning. Chain lightning is fun. The problem is, when it kills its victim with chain lightning, it will pull you and your groupmates into combat with it. If you flee, it follows and continues to attack you and your group unless it somehow acquires a different target (I don't think this is possible). This leaves me with no choice but to release it whenever it kills with chain lightning. Is this by design?