I'm not sure of the true intention of the disappear for Infernal Baroness but the AI constantly does the veil when it makes no sense.

1. In the arena, she puts the veil on herself when she is the last person alive.

2. She puts the veil on usually right before an AOE attack in the arena. On auto, the AI must know an AOE is coming or that the next attack is coming from someone who only does AOE attacks.

3. She puts the veil on herself or someone else when facing bosses with no minions. All bosses do AOE attacks.

This veil makes no sense. I don't even have the perfect veil. This is the regular veil buff.