Quote Originally Posted by Elexia View Post
That's just their unique gimmick honestly, much like you do zero damage (or severely reduced damage) to a Catuare in FFXI when they have a shirling shield around them even though you can obviously connect your weapons to them despite the shield being present. Lullaby for example doesn't even last that long to be honest. Look at moles, even though you likely killed them before they burrow, they still didn't die simply because to the server, you didn't actually get the kill shit before they burrowed.

It's why I said the biggest factor is the latency problem which makes it more of a hassle than it truly is.
It's not a gimmick of the monster, it isn't a state they enter to reduce damage. Nor is it latency (for once). They only stop taking damage when they are at 1hp, otherwise they take full damage. It's either a bug or a bandaid for one, either is bad.