Monsters attack party members when I have aggro

[KisaiTenshi]

So I was wondering why some boss monsters ignore the fact that i have aggro. The icon is red by the name in my enemy list but occasionally it turns around for a few seconds and attacks a party member. Even using an increased enmity ability like Provoke doesn't seem to make a difference on these 2 second turn arounds. Why does this happen?

That's because it's programmed to "attack the nth on enmity list" or "attack <RNG>"

If you are on the top of the enmity list, the healer is usually the second, and the healer is usually the one dodging these attacks. Otherwise the healer could always safely stand still, and ranged DPS could all stand beside them.